Bristlenose Catfish
Ancistrus sp.


Updated during June, 2024.

Warning! This article includes personal opinions and speculations!

Chapter shortcuts:

· Introduction

· Misleading pictures & misguiding sources

· Mistaken as Ancistrus dolichopterus

· Species with pure bloodlines vs mixed bloodlines & hybrids

· English common names

· Aquarium suitability

· Biofilm & algae

· Other ways to suppress and/or combat algae

· Different Ancistrus

· Color morphs of common bristlenose catfishes
  (Natural color variants and/or fancy color breeding variants.)

· Variants & traits, other than color

· Wood, vegetable fiber & aufwuchs

· Mulm

· Mud

· Botanicals can act similar to driftwood

· A balanced omnivorous diet

· Food binding agents

· Meaty foods and meaty food ingredients

· Vegetables, root vegetables, fruits & berries

· Mulberry leaves

· Weeds as food

· Fungi & edible mushrooms

· Repashy

· Seaweed & dietary algae supplements

· Commercially available dry foods

· Cleanup crew

· Natural habitats & aquarium environments

· Water parameters

· Size & age

· Soft outgrowths

· Odontodes

· Spawning caves, spawning preparations & spawning act

· Eggs, wigglers, fry & parental care

· Raising fry

· Related external links & references


There are many different species within the genus Ancistrus. It is often difficult to tell the species apart. Throughout the years I have been breeding a few natural and albino variants, which are often, but not always, referred to as:

Ancistrus cf. cirrhosus, or Ancistrus cf. temminckii, or Ancistrus sp.

However, I'm not sure of the real scientific name for any of them. Some of them may have been different species from one another, or they may have been the same species as each other, or they may have been hybrids.

Ancistrus cf. cirrhosus is one of the general classifications used online, with several similar looking species, undescribed subspecies, undescribed ecotypes, various color morphs and other variants and hybrids grouped together. Wholesalers, shopkeepers, breeders and hobbyists may also call them Ancistrus sp. or Ancistrus cf. temminckii, or other names.

Some Ancistrus sp. that are readily available in the trade, may be other pure species of Ancistrus, if the breeders have accidentally, or on purpose, conserved the species in captivity, ever since getting them from the wild. They are often difficult to tell apart from one another. Juvenile Ancistrus may change colors as they grow up into adults. Ancistrus may also change colors depending on (for example) their mood, their environment, their diet, and the light etc.

Before continuing to read, if you are unfamiliar with the genus Ancistrus, and/or if you are unfamiliar with PlanetCatfish, I recommend taking a look at the following links:

Newly found variants (or species, or undescribed subspecies, or undescribed ecotypes) of Ancistrus are still being added and sorted by scientists, traders and hobbyists. There are many Ancistrus sp. that are still only sorted by their original source location, or sometimes only using a photo, instead of a full scientific name or a scientific study. The taxonomy is being revised and added to, but it is a slow process. Taxonomy scientists have trouble keeping up with all the fishes that are occuring in the aquarium trade, while traders and hobbyists do not usually use detailed scientific means to identify their fishes. Traders and hobbyists usually prefer to simply go on calling the fishes by the same names the fishes were sold as, when they were bought, or use photographs for comparison that may, or may not, lead to the correct conclusions.

If your Ancistrus are wild caught, or if you happen to know they are descendants in a direct line from wild caught Ancistrus, from approximately the same location, please try to get a name of the location and some details about the location, if possible. Save this information for future references. If you perhaps only get the name of the exporter and the export country (that may, or may not, be the original country of the catch location), it might hopefully be better than no information at all. A few species, that a few decades ago, were often also a part of this confusion, have recently partially been sorted out from the mix, and seems to no longer be grouped together with the common Ancistrus sp. This is partially thanks to the use of L-numbers and LDA-numbers. They help to spread awareness about the diversity within the family Loricariidae.

Misleading pictures & misguiding sources:

Many old paper books and less updated/informed sources online add confusion with outdated and/or incorrect/inadequate claims/information. Pictures and video footage are sometimes shown, that are either an Ancistrus, but probably not the correct specific species of Ancistrus as claimed, or very different plecos (Loricariidae) of other genera, that are not Ancistrus at all, but still mixed in among the pictures of bristlenose catfishes. Often pictures are claimed to show a certain species, while in my opinion the claims may be wild guesses, with no real backing, or they are using other misleading sources as a guide, creating a snowball/domino effect of misleading claims.

This is not meant as critique towards those books and sources, but the learning process may get messed up, especially for beginners. I understand that it can be very difficult to identify fishes, not only for inexperienced amateurs, but also for hobbyists and professionals. We all make mistakes sometimes. Most people probably had good intentions. Apart from using incorrect names and/or pictures, they may still provide many useful, interesting and inspiring tidbits. It is just a somewhat frustrated observation of the current situation regarding Ancistrus in our complicated world.

Today, we have access to more information through the internet, and also newer books about plecos, but misinformation and misidentified species in photos, or incomplete information, is still abundant and makes it difficult when trying to accurately identify species. It is also difficult to sort out what is true or false, or just guesswork and myth, especially when the related information might actually be tied to one or more separate species, while the name and/or photo accompanying the information might be misleading.

I suggest being a bit skeptical. Keep in mind that whatever you may find, when gathering information about Ancistrus, from any source (including this article), is probably not completely 100% reliable, or may not apply to all species and variants of Ancistrus. There may be no ill intent, since there are so many mix-ups going on. Some people, or companies, may keep valuable information to themselves, while others are very open and enjoy sharing tips, opinions and experiences from their point of view.

Mistaken as Ancistrus dolichopterus:

Various common Ancistrus sp. are often mistaken as Ancistrus dolichopterus. The species Ancistrus dolichopterus is often misrepresented. To a novice it may look similar in appearance, but to experienced pleco enthusiasts it has a few traits that separates it from the most common Ancistrus sp. However, there are still several species of Ancistrus that look very similar to Ancistrus dolichopterus, so it is still complicated and confusing.

Ancistrus dolichopterus is mainly known as starlight bristlenose catfish, L183. However, it is also known as starlight bushymouth catfish, or dolly pleco, or white seam bristlenose pleco. (Swedish common names: Blå antennmal, skäggmunsmal, blå skäggmunsmal etc.)

Ancistrus dolichopterus was sometimes the only Ancistrus that was mentioned in various old aquarium books. The pictures may, or may not, have been the correct species in those various old aquarium books. Even if it was correct, some readers had no other better alternatives available, to choose from, so many other species of Ancistrus were often misidentified by aquarists as Ancistrus dolichopterus in the past. This still continues to a lesser degree today. I suggest to make it a habit to always doubt the ID of any fishes claimed to be Ancistrus dolichopterus.

Species with pure bloodlines vs mixed bloodlines & hybrids:

Many, but not all, closely related species, or maybe undescribed subspecies, or local natural variants of bristlenose catfishes, will readily crossbreed with each other. Bristlenose catfishes may usually prefer partners of the same species, but some of the slightly reluctant bristlenose catfishes may sometimes still breed with other species. This may especially happen if they are not provided with a partner of the same species, but instead find a willing partner of a closely related species. This may, or may not, be desirable depending on your point of view.

Some people feel that crossing the species (and/or undescribed subspecies, and/or local natural variants) is degrading the bloodlines. Some other people feel that the cross-species hybrids and cross-variants are interesting options. There are also people who accepts both points of view. However, the level of acceptance may vary depending on the individual situation and various external circumstances (such as maybe the use of controversial artificial breeding techniques), in each separate case.

Many bristlenose catfishes in the aquarium trade are probably fertile hybrids. The fertile hybrids may also have been crossed back and forth several times with each other through the generations. There are probably many different combinations of hybrids originating from similar species and/or undescribed subspecies of Ancistrus in the aquarium hobby.

English common names:

The majority of regular bristlenose catfishes, that look similar to each other, are also called bristlenose plecos, or bristlenose loricariids, or bushynose catfishes, or bushynose plecos, or bushymouth plecos, or bushmouth plecos, or "ordinary" Ancistrus, or "common" Ancistrus, or "mutt" Ancistrus, or other similar names, or acronyms such as BNC or BNP.

An unfortunate English name that is often used, that I do not recommend calling them, is bristlenose plecostomus. This is because using this name is misleading and adds unnecessary confusion with the common plecostomus, Hypostomus plecostomus, which is a species that grows much larger and is not an Ancistrus.

Aquarium suitability:

Bristlenose catfishes stay at a fairly moderate size, making them suitable, both as juveniles and/or adults, for most normal freshwater community aquariums. Fry and small juveniles can be kept in most normal freshwater nano aquariums, or in other aquariums dedicated to their needs and with friendly tankmates. Adults can be kept with both friendly and semi-aggressive tankmates, including most types of mouthbrooding cichlids from Africa, in medium sized aquariums and bigger aquariums.

Bristlenose catfishes may sometimes not be the best tankmates for cave spawning cichlids, since they can sometimes end up fighting over caves and sometimes eat eggs and wigglers from each other. However, juveline bristlenose catfishes and female adult bristlenose catfishes are usually OK to keep with cave spawning cichlids. In large community aquariums with a surplus of caves it is usually also not much of a problem to keep one or a few male adult bristlenose catfishes in the same aquarium as cave spawning cichlids.

Bristlenose catfishes can be kept in planted aquariums with tough plants such as Anubias, Bucephalandra, Cryptocoryne, Java fern, Java moss and so on, but are less suited for aquascapes with fragile plants. Immaculately clean aquariums, without wood and/or mulm etc. are also not really recommended for long term keeping of bristlenose catfishes, unless you have, for example, a water changing system and feed a very good diet.

Bristlenose catfishes can be kept in aquariums without plants, but plants can improve the water quality and oxygen level.

The common green Amazon sword plant can be treated as food by hungry bristlenose catfishes, that eat algae on top of the leaves and also rasp through the actual leaves and eat them too, depending on the situation. The health and size of the common green Amazon sword plant, and how hungry the bristlenose catfishes are, plays a role if the leaves get eaten, or just slightly damaged. The age/size of the bristlenose catfishes and the corresponding size of their teeth also plays a role.

Some types of plants with very narrow leaf structures are ignored, since the broad mouth of bristlenose catfishes is not suited to graze algae on very narrow leaf structures, except when the bristlenose catfishes are young fry with very small mouths, so the narrow leaves seem broader in proportion to the fry. Other plants are usually ok, as long as there are only one or a few bristlenose catfishes i the aquarium, but the plants may sometimes suffer if there is a large group of bristlenose catfishes grazing and searching for food. Some plants may get damaged from grazing, or the bristlenose catfishes may starve, in aquariums without enough food and/or algae to feed on.

Biofilm & algae:

Bristlenose catfishes are especially appreciated because they like to eat biofilm and several types of algae. They are especially good at eating diatoms (brown diatom algae), green coat algae, green dust algae (GDA) and various other types of "ordinary" green algae that grow on open surfaces.

Bristlenose catfishes like to eat many different species of algae, so they are effective as algae-eaters, but they do not like to eat all types of algae.

Bristlenose catfishes are not effective against black beard algae (BBA, black brush algae), green spot algae (GSA, dark green dots), free-floating algae (green cloudy water) and slimy nasty stinking blue-green algae (BGA, cyanobacteria, blue-green slime algae). Since bristlenose catfishes prefer to graze on flat or slightly curved surfaces, but their mouths are not good with edges, especially the edges of plant leaves may not get cleaned of algae.

Bristlenose catfishes are also not effective against green hair algae, string algae, staghorn algae, or other types of algae when such an algae grows fastened secured on edges, or on tiny objects. (Tiny objects in proportion to the size of the mouth of the individual fish, such as grains of sand.)

Bristlenose catfishes may eat green hair algae, string algae or staghorn algae under the condition that such types of algae grow on normal plain surfaces. For example, on the aquarium walls, rocks, wood, main parts of leafy plants, or similar places. Bristlenose catfishes also prefer algae that have not had time to grow into long strings. If the strings of string algae are very long, bristlenose catfishes may not like to eat them, even on plain surfaces. However, if you do a manual trim of the string algae once, so that the strings are cut very short, or if you remove all the algae once, then the bristlenose catfishes will tend to the surface afterwards, so that the string algae that tries to grow back is continuously grazed upon, and will not be able to grow long again. Bristlenose catfishes continuously graze on and maintain the surfaces that grow, for them, "yummy" algae.

If you want to keep bristlenose catfishes as algae-eaters, to clean up your aquarium, they are generally a good choice, but if you have problems with any type of algae that they do not like to eat, it may be advisable to also consider adding some other types of algae eating fishes, shrimps and/or snails, to target those specific types of algae.

Other ways to suppress and/or combat algae:

There are many ways to eradicate and/or prevent algae, alternatively, or in addition, to algae-eaters. You can use chemicals, and/or chemical filtration, and/or aquaponics, and/or manual labor, and/or technological means, change light settings (spectrum, intensity, photo/rest period etc.) change setting on aeration, change anything related to carbon dioxide (CO2), or change the water movement, change in dosing fertilizers, do water changes, siphon gravel, filter maintenance, and/or introduce specific plants to combat the algae. You can introduce other types of algae into the aquarium, that you and/or the bristlenose catfishes prefer, to compete with the unwanted algae.

Things related to algae control can be discussed in length. I'll probably write a few articles about such related topics in the future. For now, if you want to learn more about such topics, I recommend visiting some of the many links and references below this article. There, I have listed many related external links to YouTube videos, articles and explanations of different words and concepts, foods, products etc.

Different Ancistrus:

There are some species of Ancistrus that look quite different and are clearly other species, than the common bristlenose catfishes. They are usually slightly more difficult to breed and/or keep in captivity, than common bristlenose catfishes.

Popular examples of such species in the hobby, that may still be confused, or grouped, with other species that closely resemble them, but are distinctly different in appearance from the most common bristlenose catfishes:

This article is not focused on those species that might be easier to identify as other species, although this article contains some general information about plecos, including a few comparisons, this article is mainly about the common bristlenose catfishes, including suggestions on how to keep and breed them.

The common bristlenose catfishes are available in several color breeding varieties and combinations. These should not be confused with other known species.

The easy to breed common bristlenose catfishes can be seen as a gateway into trying to breed other fishes, especially different type of expensive plecos with L-numbers. If you get hooked on breeding common bristlenose catfishes, another possibility is to nerd out with line breeding, and develop an interest in experimenting with dominant and recessive genetic traits. Maybe you want to develop and stabilize your own breeding line and enhance the characteristics you are most fond of, or maybe you simply want to cross different variants for a few generations and see what happens?

Color morphs of common bristlenose catfishes:
(Natural color variants and/or fancy color breeding variants.)

  • Bristlenose Male

Wild type, natural wildform, or very similar in appearance.
  • Albino Bristlenose, Gold Bristlenose
Gold with red eyes.

Albino. Gold albino. Gold. Red eyed gold/yellow/pineapple.

Do you notice the yellow dot makings? Markings inherited from the natural form are still there. Some show these dots clearly, while others do not, depending on their breeding lineage.
  • Gold with dark/black/silver/blue eyes.

    Yellow variant(s), but not red eyes. Known by many nicknames such as:

    False L144, Ancistrus sp. (4), L144A blue eye lemon bristlenose pleco, lemon bristlenose, lemon blue eyes, L144 blue eye, blue eyed lemon pleco etc.

    Most individuals are pure yellow, but some individuals may develop one, or a few, seemingly random dark/black blots.

    According to PlanetCatfish, Ancistrus sp. (4) Black Eyed Yellow Bristlenose, is not the true L144. The true L144 was imported from Paraguay.

    There seems to be several species and hybrids that look similar in the trade. Just because they might have a similar appearance (and perhaps, or perhaps not, related to having the same type of color morph) does not make them the same species as the photographed fish with L-number it the catalog. If a fish is of a different species than the original fish in the photo of the L-number in the catalog, then it is inaccurate to call it that number. If the color morph, or age, or nuptial coloration, or gender etc. does not match, which makes it look more or less different from the picture of the L-number in the catalog, it quickly gets more complicated regarding how you want to interpret and make use of the L-numbers. In my opinion, each L-number photo mainly represents the induvidual fish in the photo. All comparisons to it will have more or less deviation, but if it is not the same species and/or not the same color morph, I personally feel it not accurate to call any other fish by that L-number if it is not both the same species and same type of color morph. If you still want to point out a connection, I think a compromise would be in the form of a comment, with a descriptive comparison to that L-number, without stating/claiming it to be (or be of) that L-number. However, currently this way does not seem to be standardized, and also not popular to use among ordinary hobbyists.

  • Pale albino???

    Pale albino is not an official name, but there seems to be an albino variant has red eyes, and the body is pale translucent/whitish color with a pink undertone. The body is either not yellow, or only very slightly yellowish tinted. In my opinion it is not yellow enough to be called gold. This type of albino is also sometimes called low grade albino, since the gold/yellow/pineapple albinos are more popular, but since low grade albino is a degrading and derogatory classification, sellers usually call them albino, or they may get mixed up with gold albino.

    Be aware that stressed, sick, malnourished (or close to dying) gold albinos may temporary loose the vibrant intensity of their color, especially if they also have not eaten color enhancing foods for a long time. Although unfortunate individuals of gold albinos in poor condition may have a confusingly similar zombie appearance, there also seem to be albinos that are healthy pale albinos?

    However, healthy pale albinos can probably develop more yellow coloration in the right circumstances? Besides color enhancing food, there may perhaps also be some relation to light, in case the pale albinos may have been kept in darkness?

  • Snow white.

    Bright pure white. Leucistic? Perhaps platinum? Has dark/black/silver/blue eyes.

  • Red, or super red, or low grade super red, or high grade super red.

    Ancistrus sp. of different shades of brownish red body colors, or brownish orange body colors, are available. These all have dark/black/silver eyes. Some breeders constantly try to enhance the red vibrancy of the body color further. Enhancing the red color can be done both through line breeding and other means, such as different color enhancing foods etc. Breeding lines that have slightly more vibrant red color than the normal/standard red are called super red. Super red can be described as a burnt orange color and these are in more demand (and more expensive at pet shops and wholesalers) than normal/standard red.

    Unfortunately, normal/standard red may also be sold as super red, even if it might be questionable if they are truly super red or not. There is no clear line between the different shades of red and the same fish can change color a bit in various environments, especially due to substrate color and aquarium light spectrum, or with different color enhancing foods. It may also vary depending on the general health condition, or just how it feels at the moment, so it can be a bit iffy to point out if they deserve to be called super red or not.

    If the red color vibrancy/intensity of the body color is in the questionable middle zone (between red and super red), such bristlenose catfishes may sometimes be called low grade super red, among fellow hobbyists and professionals. However, sellers don't like to say that, since using such a degrading and derogatory name doesn't sound good. Instead, the sellers generally prefer to call them super red and if there are any other super red, with even stronger red color vibrancy/intensity, they call those high grade super red. That way, the sellers avoid calling any fish low grade, making them all easier to sell.

  • Solid light brown.

    May look similar to red and can sometimes be changed towards a muddy red hue, depending on food and substrate, genetic lineage, light source etc.

  • Solid dark brown.

    Sometimes these are called chocolate. However, some people also call all the natural wildforms, or similar to wildforms, chocolate, no matter if they are distinctly spotted or not, but I try to differentiate them. It can be a bit dodgy sometimes, as they share a lot in common and it is sometimes hard to tell them apart.

    There are some brown bristlenose plecos in the wild, with varying amounts and intensity of spots. Sometimes the spots are so vague that the fish may seem either almost like solid brown, or maybe it can be counted as solid brown.

    If the color is a very dark brown without spots, it may sometimes be called black, but this is also a bit iffy, in my opinion.

  • Calico.

    Beige/orange-and-brown marbled coloration.

  • Super red calico.

    Vibrant red/orange-and-brown marbled coloration.

  • Green dragon.

    A slightly greenish tint on a brown/gray foundation.

    The green seems to have a slight military/olive green vibe, depending on the light.

  • Variants with spotted patterns.

    Variants with either much higher number of small spots, or extra-large and clear spots. These spots can be either gray, white, pale yellow, or bright yellow, or orange etc. These can be either from a natural wildform, or enhanced from line breeding.

    Variants with big, clear and bright yellow spots can be called lemon drop pleco.

Variants & traits, other than color:

There are both shortbody and longfin variants. These variants can optinally be combined with each other and/or with a color variant.

Longfin variants may sometimes also be called butterfly or veiltail. The original natural wildform has fins that are more robust compared to the longfin breeding variants. Longfin variants, especially super longfin variants, are more delicate and may easily damage and break their fin rays, so they should be handled gently and should not be kept with aggressive tankmates.

Some breeders try to enhance, or alter, other traits, such as the size or the soft outgrowths on the males, or the general speed of growth, or the final adult size, or behavioral traits.

Wood, vegetable fiber & aufwuchs:

For bristlenose catfishes to feel really good, and to have a better chance to live a long healthy life, I suggest that they should be provided with driftwood or bogwood (from old tree roots etc.), that they can gnaw at. Make sure that the wood is aquarium safe and does not contain poison etc.

The digestion system of bristlenose catfishes is said to benefit from the mixture of cellulose and the biofilm, algae and other microorganisms (bacteria, infusoria, fungi, tiny worms etc.) on the wood. The German term aufwuchs is often used, or sometimes the English term periphyton, is used to loosely describe it, but it does not fully explain the cellulose fiber, or whatever it is from the wood, that seems to help to prevent either bloat, intestinal blockage with constipation, and/or dropsy disease, that bristlenose catfishes can get, if their diet lacks cellulose fibers, or similar fibers. This is especially beneficial if the bristlenose catfishes happen to eat more meaty foods than normal in your aquarium, such as leftovers food from carnivores kept in the same aquarium, and/or if you are trying to condition your fishes for breeding and/or trigger breeding.

To make the aufwuchs more diverse and benificial, I suggest you consider going out in nature, find a nice freshwater body of water and gather a sample of water with mulm, sludge, leaves, algea and small pieces of sunken wood etc. The body of water might be a small pond, or a vernal pool, or a small stream, or an old rainwater barrel etc. Then put the water and the small amount of gathered material in the aquarium as a seed culture. That way, there will be a wide diversity of microorganisms introduced into the aquarium. To lower the risk of introducing unwanted fish parasites, it is preferable if the body of water does not already have fish in it. You can also choose to quarantine the microorganisms in a water bucket, water barrel, or an extra quarantine tank, for a month or longer, to be able to have more control and avoid introducing anything you do not want in the aquarium, that might be too small to notice right away, but may grow bigger, and/or multiply, during the quarantine period. If there are some microorganisms that multiply a lot, that you think your fishes will eat, you may also use is as a live food culture. If you own, or borrow, a loupe, a magnifying glass and a microscope, you can have fun looking at the microorganisms.

Bristlenose catfishes have proportionally long and narrow intestines, compared to carnivores that have proportionally shorter and wider intestines. Bristlenose catfishes should preferably be fed a mostly vegetable based diet (vegetarian), but they are opportunistic omnivores, since they also eat meaty foods when available. They can also be called algae-eaters, because when they find some type of algae they like, they eat it happily and they will not get any intestinal problems from doing so.

Unfortunately, the risk of ending up with either bloat, intestinal blockage with constipation, and/or dropsy disease increases, if bristlenose catfishes overindulge on meaty foods. This may especially happen if they don't get enough veggies and fibers to balance out their diet. Fortunately, many commercial foods made for plecos include both cellulose and other vegetable fibers.

Bristlenose catfishes do not eat the hard parts of the wood, since their teeth are not adapted to do that, but they eat the soft parts of the wood, such as parts that are slightly decaying. Bristlenose catfishes regularly rasp and eat the surface layer of aufwuchs that grows on wood, plants and other objects. Bristlenose catfishes are not relentless wood eaters, not like some other species of actual wood-eating plecos, such as Panaqolus and Panaque that have teeth that are adapted to rasp deeper when eating decaying wood, although they will also not pass up on eating other treats. The wood in the aquarium with bristlenose catfishes will get "polished" from decaying wood residue, especially if it has aufwuchs growing on it. Tiny particles of decaying wood will get swallowed at the same time as the aufwuchs.

The topic of different types of plecos eating different types of decaying wood, or aufwuchs from decaying wood, and exactly how it all works, in each different case, is complicated and a bit controversial. Some people may argue that feeding an omnivorous shrimp mix (usually made of green peas, shrimp and mussels etc.) with some algae wafers is enough to offset the need for keeping wood in aquariums with bristlenose catfishes. However, even if this might be the case, there may still be various benefits from wood, even if there is not an absolute need for it. Perhaps some of these mysteries relates to bacteria and/or fungi and/or other microbes living and feeding on the decaying wood? Hopefully, some scientists and hobbyists researching this will be able to explain more about these mysteries in the future.


Bristlenose catfishes that gnaw on wood will produce a lot of feces (fish poop) with wood residue mixed in, that eventually ends up in filters and on the bottom of the aquarium. It blends with various detritus and becomes mulm and muck sludge.

Mulm in the aquarium may play a role in keeping the digestive system of bristlenose catfishes healthy. I believe it is good enough to keep the amount of mulm at a moderate level. This is to avoid bad water quality issues and also to avoid a dirty messy look. However, if you do very frequent water changes, you might not have much to worry about the water quality issue, and if you don't keep the bristlenose catfishes in a display aquarium, but a dedicated breeding tank, then you might also not care about the dirty messy look. If so, then feel free to leave more mulm in the aquarium. Perhaps, you may even want to add mulm, from other sources, into the aquarium? Mulm may also become like a food production factory, for a food web of microorganisms, that the bristlenose catfishes can eat.

There are theories that beneficial gut bacteria may, or may not, be shared trough eating mulm and/or microorganisms living in the mulm, which may help to quickly reestablish/balance normal digestion after a period of medication and/or shipping and/or fasting. Mulm, and microbes among the mulm, may also help to establish/balance the initial gut bacteria in fry, that are starting to feed, during the first weeks foraging on their own.

If you keep a substrate in your tank, mulm will mix among the mud, sand, gravel etc.


Mud is soil, loam, silt or clay mixed with water.

Perhaps, inorganic components of mud may play some role in digestion, or other health related issues, in bristlenose catfishes? However, there are many aquarists that manage to keep bristlenose catfishes successfully in bare bottomed aquariums (with some mulm). Inorganic substrate seems to be optional? Some breeders use sand, or gravel, but bare bottomed aquariums (with some mulm) are also commonly used.

I can only speculate, when it comes to benefits, or drawbacks, for bristlenose catfishes, regarding mud. Mud may, or may not, play some (more or less), important roles in digestion for bristlenose catfishes, when they are living in the wild? It is inevitable that bristlenose catfishes will regularly ingest some mud, when they feed in their natural habitats.

Many other animals have adapted to ingesting mud, to help with digestion in different ways. I suppose, it may depend on exactly what type of mud it is (and also in what way it is used), if bristlenose catfishes benefit from that specific mud.

Botanicals can act similar to driftwood:

If you don't want driftwood in your tank, or want something in addition to driftwood, then old brown leaves from trees (leaf litter) 🍂 and other botanicals can serve a similar purpose.

Some popular fallen leaves, to use as leaf litter in aquariums, are oak leaves, or Indian almond leaves (catappa leaves), or jackfruit leaves (Artocarpus heterophyllus).

Most other leaves can also be used, as long as they are not from poisonous plants, or have been exposed to harmful chemicals such as pesticides etc. However, most usable leaves, such as maple leaves 🍁, decay, get eaten and falls apart more quickly and may need more frequent replacement, for the aquarium to look good. The leaves also provide hiding places, tannins and affects the pH and micro biology in the aquarium, a bit similar to how driftwood does. Some people like the natural look of leaves and other botanicals in the tank, but maybe or maybe not, the brownish yellow tint in the water, similar to how wood, or peat, will also tint the water.

Leaves decay in water. Eventually, even sturdy leaves decay, get eaten up and break into tiny fragmental pieces within a few weeks or months. They may need to be replaced every now and then, for the aquascape to be maintained, in aquariums stocked with bristlenose catfishes. Wood lasts longer, since it is mostly the surface layer of the wood that continuously get rasped away and get consumed together with aufwuchs by the bristlenose catfishes. Wood will slowly get smaller over time, from decay and consumption, but sturdy wood will last for several years or decades, far longer than leaves. Wood is not as flimsy as leaves. Once a piece of high density wood is waterlogged, it does not move around as easily as leaves do in the water current. This makes leaves less suited compared to wood in aquariums with high water flow.

Some breeders and wholesalers may use bamboo pipes, and/or coconut shells, which can also be used as breeding caves. Over a long time in water, the initially hard bamboo pipes and coconut shells gradually become softer as they slowly decompose, and bristlenose catfishes rasp on them, similar to wood. You can speed up the process of making driftwood, leaf litter, bamboo pipes and coconut shells softer, by boiling them in water. Boiling also helps to make them waterlogged (soaked and saturated with water) much faster, to make them sink. However, boiling also slightly shortens the time they can be used, before they fall apart, since they may decompose faster after being boiled. Boiling also extracts a lot (but not all) of the initially released tannins.

If the leaves are from a safe collecting point (no pollution, pesticides etc.) and pre-rinsed (to remove unwanted and potential contaminants, such as bird droppings, very dirty/moldy parts etc.) before boiling, then you can also make use of the boiled water (after cooling it), if you (or an aquarium friend, or a pet store) have a practical use for blackwater water extract. The water from boiling leaves, wood, bamboo, coconuts and/or other similar botanicals, becomes blackwater extract. Blackwater extract (and specific extracts, such as oak leaf extract), can also be bought in pet shops. It can be used for breeding, or keeping, any species of fish or invertebrate that may benefit from it (especially blackwater adapted residents). Some species of Ancistrus may benefit from it, but I believe it is enough with the leaves themselves (without adding the blackwater extract from boiling the leaves) for common bristlenose catfishes. However, if your aquarium water over time becomes very different from your tapwater, it may perhaps be benifical to add some blackwater extract during a large water change to balance any extreme fluctuations.

If you want to reduce tannins in your aquarium water, since strong discoloration of the water may not be to your liking, you can use water changes and/or activated carbon and/or use an electrolysis device and/or a Söchting Oxydator, or filter media such as Seachem Purigen etc.

If you want to reduce the visual effect, but without removing the tannins, you can alter the light spectrum of the light on your tank. It will impact your visual perception of the discoloration in the water. If you use warm white light, the colors of the tannins get exaggerated, while cool white light dampens the visual effect. You can experiment with different options and combinations, until you find a way, or a compromise, that you like, or find acceptable.

A balanced omnivorous diet:

If you don't want either driftwood or tree leaves in your aquarium, it becomes even more important to provide a balanced omnivorous diet of foods for your bristlenose catfishes, that is mainly based on veggies and greens.

Some people suggest to make a balanced omnivorous diet for your bristlenose catfishes, you should try to feed approximately:

  • 85% foods for herbivores. 🌿

  • 15% foods for carnivores. 🦐

These numbers are not set in stone. They are meant to illustrate an average during the course of a normal week, but can be thought of as a rule of thumb, or a general guideline. During conditioning prior to spawning (with adult bristlenose catfishes), or if the bristlenose catfishes seem to become a bit malnourished, or if their growth is very slow, it may help to try slightly increasing the protein content in their diet. If you choose to temporarily increase the carnivore diet percentage, it may still be ok as long as the foods are appropriate.

Bristlenose catfishes will graze on many (but not all) types of algae, biofilm and microorganisms. They will also scavenge from any carrion they may find in your aquarium. This is a similar diet to what most freshwater shrimps eat, but while shrimps constantly go and collect foods with their dedicated limbs, bristlenose catfishes will rasp with the teeth and lips and then suck up whatever gets dislodged into their mouth. How much algae they can eat depends on how much "yummy" algae is available. The algae will add to the herbivorous part of their omnivorous diet, while biofilm and microorganisms may add to the carnivorous part, and/or the herbivorous part, of the diet. Many microorganisms are gut-filled with whatever food they last ate, so it becomes an intricate food web with several food chains and food pyramids, but bristlenose catfishes can eat most types. If the food is small enough to swallow easily without much active resistance and does not taste bad due to toxins, there is a good chance bristlenose catfishes will feed on it.

There is a difference if you only have one, or a few, individuals of Ancistrus in an aquarium, compared to a similar aquarium with lots of them. In a heavily stocked aquarium there will probably not be enough algae and aufwuchs, growing naturally, to act as a major part of their diet, so you have to feed more food to compensate for this.

When feeding meaty foods, it is preferable if they are foods that are not prone to cause injury, inflammation or blockage in the intestines. It is preferable if meaty foods, either commercial dry fish foods with meaty content, or ingredients in homemade food, gets ground up and mixed/blended with veggies and greens before feeding, or gets alternated, and/or shuffled, with veggies and greens during the course of each day and week.

I suggest checking if the vegetables, root vegetable, fruits, berries, tomatoes, edible cactus, edible mushrooms, grains and so on, are grown in an eco-friendly way, so they hopefully do not contain pesticides etc. ✅

Even if they are not specifically marked as eco-friendly or organic, the veggies and greens still have a chance of being usable. If you want to risk using them, I suggest careful rinsing. (Rinse briefly first with pure water, then scrub/rinse/spray/dip with water containing baking soda and let it work for a while, then rinse with pure water again.) Blanching/boiling and/or peeling before usage may also help. Be aware that there are scammers who make false claims about their products, or the wind may have brought pesticides from neighboring farms, so if you do not trust both the seller and the source completely, then it is preferable to do these procedures regardless.

When feeding larger pieces of vegetables, or similar floaty/drifty foods, they can be weighed/held down with some stainless eating utensils (spoons etc.), or stainless metal rods, or other objects, to make such foods easily accessible for bristlenose catfishes. If you don't want to use your eating utensils from your own kitchen, you can go to a second-hand store and choose something different. There are many DIY and some commercially available products for holding down foods.

Food binding agents:

Some food binding agents (agar, gelatin, or gluten) can be used with caution in food mixes. I personally prefer not to use them unless I need to, since there is a risk of accidentally creating clumps of binding agent in the mix, that may cause trouble. I try to keep the water content lower in the mix, to make the disintegration of the food mix manageable during feeding. The bristlenose catfishes may also not care much if the food is spread out. Sometimes it is better to spread the food out, to avoid making your fishes fight over only one or a few cohesive pieces of food. However, without a binding agent in your mix it may create a bit of a mess with tiny pieces of food scraps that may float around in the water, or trickle down into the substrate.

Other than dedicated binding agents, some people use oatmeal, bananas and/or soybean protein isolate. These can also act as binder, although less potent than the actual binding agents, but instead they may provide nutrients and fibers.

Meaty foods and meaty food ingredients:

  • Worms. ~

    Grindal worms, microworms, black worms, tubifex and earthworms etc.

  • Insect larvae. 🐛

    Black soldier fly larvae, black mosquito larvae, blood worms, glass worms, meal worms, maggots etc.

  • Insects. 🦗 🐜

    Crickets, cockroaches etc. (Preferably in, easy to use, dry powdered form.)

  • Crustaceans. 🦐 🦀 🦞

    Daphnia (moina etc.), Bosmina (water fleas), prawns (I especially recommend northern prawn, Pandalus borealis ), brine shrimp, mysis shrimp, copepods, amphipods (scuds/gammarus etc.), isopods, krill, crabs, lobsters, crayfish etc.

  • Molluscs. 🐚 🐌 🦑 🐙

    Clams, oysters, snails, squid, octopus etc.

  • Fish meat, fish meal or fish roe. 🐟 🌕🌕🌕🌕🌕

    I suggest skinned and deboned fillets of European plaice, Pleuronectes platessa.

  • Eggs from birds. 🥚 🐓

    Hen eggs etc. (Preferably eco/organic.)

  • Heart meat or liver from birds. 🧡 🐓 🦃 🦆

    Ostrich, turkey, duck, hens etc. (Remove blood, visual fat and cartilage.)

  • Heart meat or liver from mammals. 🧡 🐄 🐖

    Beef, pork etc. (Remove blood, visual fat and cartilage.)

Vegetables, root vegetables, fruits & berries:

🥫 🥒 🥕 🥗 🍋 🍓 🥝 🍃 🥦 🥬 🍠 🍌 🍅 🍉 🌿 🌵 🌱 🍀 🎃 🧄

Some people blanch or boil the vegetables, root vegetables and culinary vegetables to make them softer. (Blanching means putting them i hot/boiling water for a short time, then cool them down.) Using them raw usually also work, and they retain more vitamins and nutrients when they are raw, but it may take a long time for the bristlenose catfishes to finish eating them raw.

Some vegetables will give off an odor, such as boiled Brussels sprouts or boiled broccoli. I do not recommend feeding raw broccoli to avoid the smell. In my opinion, broccoli is a bit too sturdy and messy (small pieces floating away) to be eaten raw by bristlenose catfishes. You may want to try a few different vegetables, to see which ones your fishes enjoy, and how your aquarium smells.

Evaluate if whatever you feed may cause bacteria, infusoria and/or mold to multiply rapidly in your aquarium, especially if you overfeed. Some foods can be left in the aquarium, to be munched on, for one or a few days, while leftovers of some other foods should preferably be removed after a few hours. Some vegetables can be used as part of a staple diet, while others work better as occasional treats, or only for use if you have nothing better available.

Adjust what vegetables and how much you feed, to your water change routines and to what is on sale (or in season) at the grocery store, and what you yourself like to eat. That way you can share food with your fishes and there will be less risk of wasted food. You also get a habit of keeping healthy foods in your fridge and freezer. Some vegetables contain more or less water, and hence more or less nutrients per volume.

Some of the most commonly used vegetables and/or culinary vegetables, where you do not need to worry about disposing of any seeds, are:

Green peas (shelled/mixed/pureed), green beans, spinach, broccoli, Brussels sprouts, pak choi (bok choy, pac choi), collard greens, mâche (mache, common cornsalad, lamb's lettuce, Valerianella locusta), and various different types of lettuce/salads.

Not all varieties of the same species of vegetable are the same, so you can try a few different types and brands. Experiment to see which ones work best for you and your fishes and if you want to use them raw, blanched, or boiled.

Pureed vegetable mixes can be combined/mixed/blended with some meaty pureed food-ingredients and frozen in thin layers, in flat plastic bags, and the stored in the freezer.

Canned green beans 🥫 as food for bristlenose catfishes:

  • Preferably French cut (French style).
    (Fancy cut also work, but they are less convenient for fishes to eat.)

  • Preferably without added salt.
    (Salted usually also work, but be careful if you keep salt sensitive tankmates.
    Too much salt in the diet is not healthy for humans.
    If you yourself often eat salted canned green beans, keep in mind your sodium intake.)

  • Canned green beans have a softer texture compared to raw and frozen green beans.
    (Bristlenose catfishes enjoy the soft texture and taste of canned green beans.)

Some root vegetables that you can try are carrots, sweet potatoes and yams.

I suggest to avoid potatoes. 🥔 They can be used, but will cloud the water.

Some fruits and berries, that can be used as culinary vegetables, can be used to feed bristlenose catfishes.

It is preferable to either choose seedless variants, or to remove the seeds when feeding culinary vegetables. For feeding bristlenose catfishes, one of the most commonly used culinary vegetable, that you may, or may not, want/need to remove the seeds from is zucchini (courgette). Some other examples are:

Cucumber, watermelon, cantaloupe (rockmelon, sweet melon), tomato, various Cucurbita (pumpkin, squash etc.), bell pepper (paprika, sweet pepper, capsicum) and strawberry.

Zucchini may sometimes contain toxins, but when so, it becomes very bitter. If it tastes bitter, don't use it. Zucchini is more nutritious than cucumber and pumpkin etc.

I suggest to avoid egg plants (aubergine) 🍆, since egg plants may sometimes contain toxins and are not very nutritious either, but it can be used with caution.

I suggest to avoid hot peppers. 🌶 I'm not sure how potentially dangerous each type of hot pepper might be to bristlenose catfishes, or other living organisms in your aquarium, but I think it is better not to test it.

If you use bell peppers, then I suggest using yellow, orange or red bell peppers, instead of green bell peppers. Bristlenose catfishes seem to like like the taste of them more than the green bell peppers. Especially orange and red bell peppers also have a higher concentration of antioxidants such as vitamin C, beta carotene etc.

A few fresh pressed cloves of garlic 🧄 can be used for medicinal purposes in a normal batch of homemade frozen fish food mix, or added diluted in water to dry or frozen food and let the food soak in it. It is used when there is reason to suspect parasites or intestinal trouble, or for preventive measures. Many aquarists says that a little fresh garlic oil in the fish food mix can increases appetite and health in some fishes. I do not have evidence of if, or how, it works. Some people think it still works after being frozen, although theorize it may perhaps affect the potency, while others prefer to add it by soaking food in a glass of water with it right before feeding. Garlic will leave the typical garlic smell. Some people enjoy and prefer the smell of garlic to the original smell of the fish food, while other people (like me) don't. There are rumours that garlic may be detrimental to some invertebrates, but used sparingly it seems generally ok to use?

Fruits and berries can be used in moderation and with caution in small amounts when mixed/blended together with other foods. A little freshly squeezed lemon juice 🍋 and a few strawberries 🍓 (with the seeds removed) or a kiwi 🥝 (with the skin and seeds removed) can all add vitamin C, antioxidants and a fresh smell to a fish food mix. Usually, but not always, ripe fruits and berries are better suited than unripe ones, since they transform and improve in both taste and texture when they become ripe. However, avoid feeding too much of any sugary foods. Bristlenose catfishes may not like to feed on some foods separately, but may eat it in a mix/blend with other foods.

Bristlenose catfishes do not like to eat bananas 🍌 separately. If you still want to use bananas, I recommend only using ripe and eco-friendly (organic) bananas and mix/blend the bananas with other ingredients.

Remove the banana peels. I suggest that you preferably also remove the seeds in the banana core. (You can cut out the middle and eat the part with seeds yourself.) Removing the banana seeds probably does not make any difference if you intend to only use the food for adult bristlenose catfishes. However, I suspect it might be better to remove the banana seeds as a precaution, if the food is intended for very young fry. Puree the bananas and mix/blend/grind with a lot of other foods in an omnivorous food mix. Bananas can partially act as a binder and adds vitamins and minerals, but don't use too much since the bristlenose catfishes are not fond of bananas.

More about feeding vegetables, root vegetables and culinary vegetables:

Commercial fish foods often include powdered dry alfalfa sprouts as an ingredient, which works very well. You can also use powdered dry alfalfa sprouts as an ingredient and blend it with other foods in a food mix. I do not recommend feeding fresh raw alfalfa sprouts, it's inconvenient for bristlenose catfishes to eat.

Plenty of vegetable matter eaten by your fishes will result in a lot of feces (fish poop) with vegetable residue mixed in, that eventually ends up in filters and on the bottom of the aquarium, as it turns into mucky detritus mulm, but may also promote growth of algae, aufwuchs, plants, infusoria, snails, bacteria etc. Make sure your water quality stays ok. Do water changes when needed and siphon out some (but not all) of the detritus mulm.

Keep in mind that liquids and small particles from the food will leak out into the aquarium water during feeding, this may increase the growth of bacteria, infusoria, algae, fungus, aufwuchs, plants, snails, scuds, planaria etc. This may be a good thing, or a bad thing, depending on your point of view.

Mulberry leaves:

Dry, fresh, blanched, or boiled mulberry leaves 🌿 are recommended. Both bristlenose catfishes and most types of freshwater shrimps enjoy mulberry leaves. After boiling the mulberry leaves you can drink the water as green tea. 🍵

When drying leaves, to save them and use them later, perhaps for when they are not in season, an old trick you can use is to put leaves among the pages of disposable blank notebooks. This prevents the leaves from curling up, retaining a nice flat pretty shape to graze on by bristlenose catfishes. If you intend to make powder from the leaves, it does not matter if they curl, you can dry them any way you want.

Weeds as food:

Usually, some fresh young tender leaves of dandelion, stinging nettles and Plantago major can be used blanched, or raw if you rinse and soak them. If you want to use older tougher leaves, then boiled leaves may be more appreciated.

  • Leaves of dandelion.

  • Leaves of stinging nettles.

    • Used as an ingredient in some popular commercial pleco foods.

    • Available in health stores in dry powdered form.

    • EN Wikipedia - Stinging nettle

    • Soaking stinging nettles in water, or cooking, removes the stinging chemicals from the plant, which allows them to be handled and eaten without injury. (EN Wikipedia)

    • In its peak season, nettle contains up to 25% protein, dry weight, which is high for a leafy green vegetable. (EN Wikipedia)

  • Leaves of Plantago major.

Fungi & edible mushrooms:

Bristlenose catfishes probably get various fungi in their diet, when they graze aufwuchs on wood and leaves in the wild. When bristlenose catfishes are kept in aquariums, edible mushrooms are probably good supplements to their diet?


A favorite, among many breeders, is to mix different blends of Repashy powders in hot water and let it cool into gel food. The gel food can be fed as cubes/pieces, or you can also use it as a coat/layer on small stones, pieces of driftwood and other similar aquarium decorations, and let the bristlenose catfishes clean them.

Seaweed & dietary algae supplements:

Marine seaweed/algae (kelp, nori etc.) can be used, but I prefer feeding sinking pellets, or wafers, with it as an ingredient, to avoid making a mess in the aquarium.

Some people use powdered spirulina and/or Chlorella as a supplement ingredient in homemade food mixes (for fishes of all ages), and/or use the powder directly as food for fry, by putting it into the water and stir to make the powder sink to the bottom. There are several types of "spirulina", that may be very different from each other, so not all of them are recommended. Make sure they are graded fit for human consumption and perhaps try another type, if you encounter problems. Some aquarists also warns of "black liverspots" appearing on some types of fishes, when overdosing spirulina.

Astaxanthin is often used in small amounts both as a dietary supplement in fish foods, and in health supplements for humans. It is known as a powerful color enhancer for fish, but also has other health benefits at low dosage, but can get dangerous at high dosage.

  • EN Wikipedia - Astaxanthin

  • Mikolji - YouTube video:
    Exclusive interview with Discus fish legend Marc Weiss

    Feb 8, 2014 [Original long full version including making fish food. 1 h, 3 min, 40 s.]

    (Ivan Mikolji interviews Marc Weiss, a famous aquarium hobbyist who specializes in Discus fish. Marc Weiss has some controversial opinions about fish food. I might not agree on everything, but I think it is very good to sometimes try to see things from a different point of view, not simply going along with the mainstream. Challenge your thinking and see if there is perhaps something you can learn? Maybe you can derive new conlusions, on how you think nutrition works.)

Commercially available dry foods:

There are many types of dry foods in aquarium shops that are made for plecos and other fishes with similar dietary needs. Commercially available dry foods include wafers, pellets, granules, tablets, vibra bites and flakes etc. These can be used as a staple diet for bristlenose catfishes. Some foods may contain a lot of meaty ingredients. Try to balance the diet of your bristlenose catfishes by also feeding veggies etc.

If you happen to have pellets of a floating type, that you want to feed to your bottom-feeders, my tip is to first put the feeding portion in a glass of water. (If you want, you can also add some other foods and/or liquid vitamins etc. to the water.) Wait until the pellets have absorbed some moisture to become soft and have finished most of their expansion (usually after about 10-20 minutes), then squeeze the pellets under water until the gases inside are expelled and the pellets sink.

Flake food can get a bit messy since they float and spread around the aquarium. Bristlenose catfishes prefer to feed at the bottom, or on substrates. If you have other types of fishes in the aquarium that you feed with flakes, some of the flakes that get to the bottom will get eaten by the bristlenose catfishes. Try not to overfeed if the flakes are made for carnivores. If a lot of flakes get to the bottom, it is preferable if they are mostly vegetable/algae flakes, so the bristlenose catfishes can eat them without problems.

A small amount of meaty types of flakes is ok, as long as the bristlenose catfishes also get other foods to balance their omnivorous diet. To deliberately make flakes sink, put the flakes in a glass of water, stir, then pour the water with the submerged flakes into the aquarium.

A small/modest amount of very finely powdered food can be spread around in the aquarium, preferably on a regular basis. The powder may partially directly become food for bristlenose catfishes, but the powder is mainly meant to feed the biofilm and microorganisms. As the the biofilm and microorganisms grow and multiply, larger algae and plankton also grow. All together they can become part of an ecosystem with regenerative aufwuchs, that bristlenose catfishes graze on.

Cleanup crew:

Some people like to keep snails together with bristlenose catfishes. Be aware that a few species of snails may eat eggs from bristlenose catfishes, so some species of snails may be better tankmates than other species of snails, in breeding aquariums.

Snails help to clean up food leftovers that might start to mold, and/or rot, if left too long, especially if there is gravel in the aquarium. Food particles may fall down among the gravel, but burrowing snails can easily get to these concealed food scraps among the gravel. Bristlenose catfishes prefer to mostly eat food that is easy to access on top of the gravel and do not like to dig too deep into the gravel for food. The snails will also act as a buffer, to slowly eat food leftovers, even in aquariums without gravel. Tiny snails may also eat food particles that get sucked into filters. This may be very helpful if you often overfeed the bristlenose catfishes.

Some aquarists keep Corydoras catfishes, or loaches, or shrimps, or tubifex worms, or blackworms, or scuds, instead of, or as an addition to snails, as gravel cleanup crew. If you don't deliberately introduce anything to feed on the tiny food leftovers, there will still come different types of infusoria and maybe accidentally come planaria, nematodes, or hydra, or leaches and so on, to fill this void in the food chain. Especially, if you feed live foods or introduce plants, gravel, or other things that critters may hitchhike with, from other aquariums, or from other bodies of water.

Natural habitats & aquarium environments:

Different natural habitats where Ancistrus live in the wild are located in the Amazon and neighboring areas in South America. Many natural habitats are being destroyed at an alarming rate. Some habitats get changed because of humans building hyroelectric dams, and deforestation to rear cattle and the use of pesticides on crops. Humans are also causing invasive species to spread, making preservation of indigenous (native) species quite complicated.

Bristlenose catfishes try to stay close to the substrate, such as wood, stones, leaf litter, vegetation, and other objects. They can attach themselves by sucking with their mouths and scrape algae and aufwuchs with their specially adapted teeth.

Bristlenose catfishes have armored bodies and they can usually handle moderate aggression from tankmates, but their eyes and fins may get damaged by aggressive tankmates, especially if there is nowhere to hide. I recommend having caves and/or other hiding places in the aquarium, where the bristlenose catfishes can retreat.

Some Ancistrus are highly adapted to living in blackwater in the wild. They may be somewhat delicate, if not kept in similar blackwater conditions in captivity. Other Ancistrus may live in other biotopes, but can probably spread to the sorroundings during rainy season? The ones that are used to switching conditions in the wild, are probably easier to keep in average community aquariums.

Some Ancistrus are highly adapted to living in fast flowing water in the wild, while grazing on algae and other aufwuchs on rocks and forage/scavenge for food, but may also be found in other places, such as flooded forest etc. depending on the season.

Ancistrus have the ability and tendency to sometimes climb up waterfalls, if there is moderately running water and something appropriate to build traction and suction on.

The water may flood or drain, and the weather is not always the same in most places in the Amazon. The natural environment changes through the seasons and (more or less) during each day and night. During the rainy season the rainforest can get flooded and the water level may rise several meters in rivers and brooks, spilling over and creating temporary wetlands where there was dry land during the dry season. There are various blackwater habitats, whitewater habitats, springwater habitats etc. (Clearwater rivers are very rare in the Amazon.)

Below are a few links to videos and playlist on YouTube related to fishes in the Amazon. These videos are not specifically about Ancistrus! Still, I think they are helpful to get an idea about the situation in the Amazon. The water in the Amazon is usually either blackwater (stained dark by tannins), and/or whitewater (opaque gray/white from suspended silt). Even if the water is clear there may be powerful strong rapids and/or great depth, making filming and photographing difficult/dangerous or impractical/impossible. Only a few exceptional places, such as where clear ground water comes up from springs, or where the water flow subsides, are especially suited for filming underwater documentaries, but this is only a sneak peek and can not represent the whole Amazon.

Water parameters:

Common bristlenose catfishes can usually accept a variety of water parameters. They can temporarily survive more extremes, but here are some general guidelines:

A pH of about pH 6.5 (5.8 - 7.2) is usually recommended, but as long as their other needs are met, they can usually thrive and successfully spawn in a very broad pH interval. Approximately from about pH 5.0 to pH 8.5 is tolerated ok in aquariums. There may be differences between local natural populations, and different breeding strains, regarding what they prefer and tolerate. Some might tolerate or prefer a more extreme pH, either higher or lower, than others.

Temperature of about 24°C (21-27°C) or about 75°F (70-80°F) is primarily recommended. However, common bristlenose catfishes tolerate a few degrees even lower and even higher, assuming all other water parameters are ok. If the aquarium is well aerated, the water quality is ok and other environmental, nutritional and size compatibility related requirements are met, common bristlenose catfishes can tolerate being kept together with discus, with temperatures of about 29°C (28-30°C) or about 84°F (82-86°F). However, constant high temperature (such as in a discus aquarium), or low temperature, outside the primarily recommended temperature ranges, will have a great influence on breeding cycle, longevity, immune system, digestion, metabolism, growth rate etc.

The concentration of dissolved dioxygen (oxygen gas O2 in the water) should be kept fairly high. If you have plants in the aquarium you can add carbon dioxide (CO2) and the plants will use the carbon and release dioxygen through photosynthesis, so you can get a higher oxygen content in the water, than what is possible through aeration with normal air. Aeration is recommended, especially during hot summer weather, if you do not have much plants. If there is a general lack of oxygen gas, or a disturbance in the nitrogen cycle, the bristlenose catfishes will congregate closer towards the surface and frequently rush to the surface and gulp air, trying to survive by absorbing oxygen gas from the air in their intestines, which is an adaptation they have, to temporarily survive low oxygen conditions. If you notice such behavior, investigate and fix the problem as soon as possible.

General water hardness of about 6-20 dGH is recommended, but common bristlenose catfishes are usually ok within about 4-25 dGH. Assuming all other water parameters are ok, common bristlenose catfishes temporarily tolerate even softer or harder water. They can often live in soft water in nature, but lower than about 4 dGH becomes dangerous in aquariums, since the other water parameters, especially pH, may start to shift and fluctuate dangerously, putting the biological balance at risk. Some species of Ancistrus may not be as tolerant regarding the water, hardness as common bristlenose catfishes, and may prefer/need soft water to thrive and breed.

Most Ancistrus live mainly in freshwater in the wild, so it is not recommended to add salt (NaCl) to the water, unless it is for medical reasons. Ancistrus can usually handle moderate amounts of salt, if acclimated properly. Some species of Ancistrus may also be found in slightly brackish water in the wild, but I do not recommend keeping common bristlenose catfishes in brackish water aquariums.

Size & age:

Male bristlenose catfishes can grow to about fifteen cm (about six inches) and females can grow to about twelve cm (about five inches). These measurements are standard length (SL).

There have been occasions when some individual bristlenose catfishes have grown slightly larger than normal, but it is rare for them to grow bigger. Some breeding lines, or some species, may also not grow quite as big as others. Some individuals may grow a bit slower or faster, eventually ending up either smaller, or bigger, than their siblings. For bristlenose catfishes to grow bigger than normal they need to have been fed very generously for several years and kept in good water conditions, starting all the way from when they are small fry, to avoid any growth inhibiting upbringing that may lead to stunted size. Very frequent breeding may hamper potential growth and make the breeding bristlenose catfishes stunted, or not reach quite as big size as they could have if they did not breed so often.

If you want the bristlenose catfishes to grow bigger, it may help to keep the males and females separated for moderate periods of time. I do not recommend separating them too long though, since I suspect there might be a possibility that the females may become eggbound (spawnbound), possibly leading to their death, although I'm not completely sure. Regarding a male, well it will grow faster if it not breeding and also may grow faster if it does not have a breeding cave to guard, but it doesn't seem right to raise him without occasionally letting him gain some breeding experience and parental care experience. His soft outgrowths may also not look as impressive during his growth period, if he never gets to breed and interact with females until his body is fully grown.

I suggest that you avoid keeping bristlenose catfishes in very dense populations, although it is certainly possible to do so. Keeping them in moderately populated aquariums may let them focus on eating and growing, instead of breeding and competing with each other. Also, if there is a power outage, a power failure, an equipment failure, or a random fish dying in the aquarium, there is still a good chance of survival, for the remaining bristlenose catfishes, if there are not too many inhabitants in the same aquarium. Overpopulated tanks are sensitive to disturbances. The biological system may end up crashing with a domino effect. Bristlenose catfishes in an overpopulated aquarium may all end up dying together because of ammonia poisoning, or nitrite poisoning, or oxygen depletion, if an accident happens, especially if you are on summer vacation at the time, and can't immediately deal with the situation. This is unfortunately a fairly common cause of bristlenose catfishes not reaching their full size and also not their full age potential.

Bristlenose catfishes that are kept in optimal conditions for longevity are rumored to, on a few occasions, have reached up to about 20 years of age, but this seems to be extremely uncommon. There are quite a few more trustworthy cases when they have been confirmed to have reached about 10-15 years of age. I have kept only a few individuals that have reached that age range, but I know other people have also kept individuals that reached that age, but these are still statistical outliers. If kept in good conditions and there are no catastrophic accidents, there is a good chance that a few individuals in a group of bristlenose catfishes may reach about 8-10 years of age, but it is unlikely that all individuals in a group of juveniles survive to all eventually reach that age.

It seems most bristlenose catfishes usually do not die of old age in aquariums. Some may die of cancer, but usually bristlenose catfishes in captivity die because of either temporary, or long term, poor living conditions, or something inappropriate (or bad) about their diet, or predation, or bullying, or equipment failure, or other accidents.

Soft outgrowths:

Male bristlenose catfishes get very soft outgrowths on their snout/head, resembling elastic miniaturized deer antlers, or bushy fleshy tentacles. I'm not sure if these soft outgrowths exactly fit the description of tubercles, but they do share similarities with tubercles. These soft outgrowths are missing, or occur very sparsely, among the females.

I suggest to avoid using females with soft outgrowths for breeding, if you can get other more feminine females instead. Even if the soft outgrowths are small, it is not a trait aquarium keepers generally want to enhance in female Ancistrus of future generations.

My suggestion about the preservation and enhancement of secondary gender characteristics (gender dimorphism) also applies to males, but in reverse. Try to use males with clear male Ancistrus characteristics for breeding, such as lots of soft outgrowths on their snout/head. It is generally preferred if the gender differences are kept as clear as possible through the generations, so people can tell the difference easier.

It is not yet proven what purpose the soft outgrowths may serve. It is theorized that the soft outgrowths may play a role in how the males stimulate females into breeding. One such theory is that perhaps the soft outgrowths mimic a tactile feeling similar to a brood of fry, like a mimic decoy? Maybe the female like the soft outgrowths on the male? If this is so, it may be a cheat the male uses, that makes it seem as if the male is dependable and already doing a good job as a parent? Some other theories are that perhaps the soft outgrowths may help to keep the eggs clean? Perhaps the soft outgrowths can help the wigglers and fry to recognize their father and make them feel safe in the cave? Perhaps the male uses them to feel the vibrations of the wigglers and fry in the cave? Perhaps it helps to hide and camouflage the fry from an intruder that tries to raid the cave? It is unknow to me if these theories, or other theories, are correct or not. The theories still need some sort of official verification, or a probability assessment. It would be interesting if there were studies made to investigate the chances of these theories being true or false.

The soft outgrowths vary slightly in size over time. The soft outgrowths of dominant males get slightly bigger during breeding season. During off season the soft outgrowths may get slightly smaller, if there are no females to breed with for a long time. If there is a male with small soft outgrowths, that is constantly oppressed by one, or several, dominant males in the same aquarium, the soft outgrowths may stay small and stubby, but if the oppressed male is moved to another aquarium without oppression, or if the dominant males are removed, the small and stubby soft outgrowths may suddenly rapidly start to grow bigger, especially if there are females around that want to breed. However, there are also genetic limitations. Some individual males seem to have a genetic predisposition to be able to grow larger soft outgrowths than others. There is also a loose template size, affiliated with different natural strains, or breeding strains. The soft outgrowths may also get smaller if a male is kept with other very aggressive fishes, that injure the soft outgrowths, since it takes time for the soft outgrowths to grow out again if they are bitten off.

Some strains and species of Ancistrus get soft outgrowths that branch out (once, or more than once) as the soft outgrowths grow longer, while other strains and species of Ancistrus mainly have soft outgrowths that do not branch out, or do not branch out much, even if they grow thicker and longer. The amount of branching may also differ, to some degree, between different individual males, even if they are of the same strain and species.

The soft outgrowths are not odontodes! Many people, including reputable aquarists, have unfortunately often called them odontodes, but this is a wide spread misconception.


A bristlenose catfish has cheek odontodes on each side of its head. The cheek odontodes can be folded into the head and are usually mostly hidden. It is not strange for people to confuse the soft outgrowths with cheek odontodes, but they are not the same thing! Odontodes come in different varieties and sizes. Odontodes are not exclusive to Ancistrus. Many other catfishes and some other fishes also have odontodes.

In addition to the cheek odontodes, bristlenose catfishes also have other types of odontodes, both on their armored bodies and on their fin ray spines. The cheek odontodes and the pectoral-fin spine odontodes are usually noticeable with the naked eye on adult bristlenose catfishes. The size of the cheek odontodes and the size of the pectoral-fin spine odontodes can often be helpful when determining the gender of various different species of armored catfishes, since they are, usually, proportionally a bit longer and more robust on males. Odontodes are also called dermal teeth. They have a hard outer structure, but a soft inner structure, similar to how teeth are constructed.

On each side of its heads, located below the eyes, a bristlenose catfish has hard sharp cheek odontodes, that it can fold inwards, to normally keep them mostly hidden, or flex them outwards from its head (in a scary way) when it wants to use them. These cheek odontodes of Ancistrus are also known as interopercular spines, or interopercular odontodes. They are a part of an erectile cheek-spine apparatus. These cheek odontodes on Ancistrus are like a bunch of hooks, curved needles and curved spikes. They can be used similar to spiky hook weapons during disputes (either to threaten or to injure), or can be used as an anchor inside caves, or as a defense against getting swallowed by predators. Ancistrus, especially adult males, have proportionally quite big cheek odontodes in relation to their body size.

A few other genera of catfishes also include species with proportionally big cheek odontodes. They also have them as interopercular spines and a part of an erectile cheek-spine apparatus. Some examples are Panaque, Spectracanthicus, Hypancistrus, Pseudacanthicus, and Panaqolus etc. Those genera usually have more straight needle shaped spines, sometimes very long, but usually not hook shaped, or the hooks may not be curved very much. However, some (but not all) species of Lasiancistrus, Hopliancistrus and a few species of other genera also have hook shaped cheek odontodes, sometimes very similar to Ancistrus, but they are not as popular as Ancistrus in the aquarium trade.

It is not practical to have very robust and big cheek odontodes sticking out all the time, all year long, but the adaptation with the interopercular spines on the erectile cheek-spine apparatus lets them transform, to keep them folded back and hidden when not needed, so they are not in the way in daily life, but whenever there is a use for them, they can quickly be erected.

On most other genera with cheek odontodes, the cheek odontodes are usually smaller in relation to the size of the fish. Yet some other genera also have other types of cheek odontodes, that stick out all the time and can't be folded back, but the spikes are usually not as big and robust, but instead there are usually more of them packed together, and they often look similar to tiny spiky hair stubble on a paintbrush. These can often be useful to inspect, when determining the gender of species that have them, such as Sturisoma.

During spawning, the cheek odontodes on bristlenose catfishes also get flexed and folded a few times, both by the male and the female. During the spawning interaction, the cheek odontodes are used in a much more restricted and gentle way than during real fights, but the breeding pair might on occasion still end up with a few minor scrapes.

Adult bristlenose catfishes should not be kept together with any voracious predatory fish that has a mouth big enough to put an adult bristlenose catfish in its mouth and try to swallow it. This is because it may end up damaging, or even kill, both prey and predator. When bristlenose catfishes are in a crisis, their cheek odontodes can stay constantly erected and they also spread out their pectoral fins. During dominance sparring with other bristlenose catfishes they "jab" almost like boxers with their cheek odontodes, usually aimed towards their opponent's cheek odontodes. As the bristlenose catfishes grow older, the cheek odontodes get bigger. Males get bigger cheek odontodes than the females. When two large males of similar dominance levels fight, their cheek odontodes can sometimes get tangled up with one another, with their hooks, similar to how stags (male deer) lock horns when competing during mating season, but they usually untangle themselves after a while.

Fights can be hectic, but usually don't cause too much damage as long as the aquarium is big enough, and/or decorated with obstacles, so the loser can get away when the time comes. Plenty of caves and a surplus of hiding places, enough for all adults to feel safe, and have their own space away from each other, can lower aggression. An alternative is to have no caves, so there are no good spawning caves to fight for. Only having one or a few caves can work, if there is only one dominant male, or all the dominant males get a cave and location they like. However, the adult females and non-dominant males also need places to retreat, but can make do with hiding places other than caves.

Sparring, or minor disputes, or scuffles, can also happen at other times, both within the same gender or across genders. A random dominance fight can happen during a meeting by accident, or more often when two individuals want the same piece of food. Fights and disputes may also happen when a female that is ready to spawn, but more than one male is interested, so they compete, or the dominant one tries to chase away the less dominant one, that may be interfering and probably tries to take advantage of the situation. Usually, the biggest male wins, since males are more aggressive, have bigger odontodes and are stronger, but if a small male, or a weak male, fight with a large female, then the result of the battle may end up either way. A small dominant and aggressive male may also win over a non-dominant big male, or a big male in bad condition.

Videos of males sparring:

Cheek odontodes can be a problem when netting bristlenose catfishes, because of the hooks. Netting small juveniles may be OK, but large juveniles or adults (especially big alfa males) often get stuck in the net with their cheek odontodes. If possible, try to use other methods, instead of regular ordinary nets, when moving adult bristlenose catfishes. Some nets are better than others and easier to untangle from the cheek odontodes. You can also use other methods, such as catching the catfishes by hand (preferably with gloved hands for protection) or using plastic bags, or a strainer, or a plastic cup/box etc. If an adult male needs to be moved and it lives in a cave that is made of something small enough to be easily moved, it is usually better to move the whole cave together with the male, instead of taking out the male from the cave.

Bristlenose catfishes can lodge themselves inside caves with both their cheek odontodes and their pectoral fins. Some of the fin rays also have noticeable odontodes, especially the first fin ray of each pectoral fin. These odontodes on the fin rays get slightly bigger on males than on females, but the spikes are not even close to the size of the cheek odontodes.

Bristlenose catfishes can be difficult to remove from inside a tight hole in driftwood etc. If I ever need to force out an adult bristlenose catfish that is lodged tight in a cavity, I usually try using air bubbles from an air pump. I put the air stone (or the bare end of the air hose) as far inside the cavity as possible, while the hole is under water. This stirs the water with lots of air bubbles inside the cavity, preferably crank up the airflow to create a lot of bubbles. Eventually the bristlenose catfish will usually choose to let go by itself and work itself out to escape the annoying air bubbles. However, it might take a few minutes if the bristlenose catfish is stubborn. Unfortunately, if the cave has a labyrinth/maze design, or more than one opening, this trick is less likely to work. An other option, if you are not in a hurry, is to avoid trying to get the bristlenose catfish out of the cave, but instead wait for an occasion when the bristlenose catfish has already left the cave on its own accord and then very quickly remove the cave, before the bristlenose catfish can go back in and lodge itself there. That way the bristlenose catfish can no longer hide in the cave and should be easier to catch in the aquarium.

Spawning caves, spawning preparations & spawning act:

The male bristlenose catfish will choose a favorite cave in the aquarium. It is preferable if there is only one entrance to the cave. If it is a tube, then I suggest closing off one end (either plug, or cap it), while leaving the other end open. It is also preferable if the size of the entrance is a size that the male can easily defend by blocking, while at the same time being able to fan water, with his fins, on a potential brood. This can help the male prevent invaders from entering, while he is tending to his brood in the future. It is better to prevent invaders from entering in the first place, than having to chase the invaders away from inside the cave after they have already entered the cave.

The cave may be in a driftwood cavity, in a plastic tube, in a bamboo tube, in a fake miniature shipwreck, or a coconut shell, a stone cave, under a broken ceramic flowerpot, in a ceramic watering spike, in an empty barnacle shell, or in dedicated pleco caves from the pet store, or something else you have put in the aquarium.

If you use a plugged (or capped) PVC tube, I suggest rugging the insides of the tube with fine grit sandpaper, to create a rugged surface, so the adhesive eggs can stick more easily to the PVC, to avoid having the eggs sliding out of the cave.

If you use a ceramic cave, or a slate cave, or hard plastic cave, make sure there are no skarp edges inside the cave left from manufacturing. Bristlenose catfishes can get damaged, especially on their sensitive bellies, if they cut/scratch themselves on any sharp protrusions. I suggest using a tile file, and/or sandpaper, to file down any sharp protrusions.

In a desperate situation, a male may also choose a less than ideal place, if he does not find a good cave in a position he likes, or if you do not provide any good caves for him. The male usually stays in his favorite cave most of the day except at feeding time, but may roam around at night or sometimes during the day, when he does not have a brood to guard. He still does not like to leave his cave unattended for too long, since other fishes, or critters, may try to occupy his favorite cave if he is not there to defend it.

To entice the bristlenose catfishes to spawn, I suggest doing normal water changes, or do water changes with slightly cooler water, in combination with feeding plenty of good foods. Preferably (but not necessarily) add some tiny live foods to their diet. Sometimes, it can be enough to increase aeration in the aquarium, or to do maintenance on a clogged-up filter, to trigger spawning. Usually, it can act as a trigger to do a water change during a heavy rain, since bristlenose catfishes, similar to other many other fishes, seem to be able to sense the change in barometric pressure, similar to the rainy season in nature, when it is often spawning season for many fishes.

If it is during a long summer heatwave, the water might get too warm and the bristlenose catfishes may not want to spawn, then it might be good to lower the temperature. Turn off heaters, or lower their setting. Use window ventilation, or an air fan blowing on the surface of the water to increase evaporation cooling. Maybe try an AC in the room, or a chiller connected to the aquarium, or using ice packed in bottles or bags to float in the water etc. Excessive heat also decreases the concentration of dissolved gasses in the water, while simultaneously increasing the need for oxygen gas for bacteria and fishes by speeding up their metabolism due to the heat. If the water is hot, it may cause a serious lack of oxygen gas in the aquarium. However, if your bristlenose catfishes are not in danger and don't show any symptoms of distress (such as going up to the surface and gulping air, or acting lethargic, or getting sunken eyes etc.), then you could also choose to simply wait until the heatwave is over, or until a heavy rainfall, before trying to trigger spawning again.

If a female in the aquarium is ready to spawn, the male will entice the female into the cave. The spawning usually takes place in the evening after the lights are out. (The first time I observed the actual spawning, was when I happened to look into the aquarium one hour after the timer had shut off the light. I have witnessed spawning several times since then, with similar timing about an hour after the lights are out, but foreplay/courtship interactions between a male and a female may also happen at other times, sometimes going on for hours.) The male waves his caudal fin and the female swims into the cave.

The foreplay/courtship is repeated until the female decides to lay all her yellow, yellowish or yellow-orange eggs. I suspect the milt released by the male might play a role in triggering her to lay eggs. Normally, if she is not interrupted, the female can squeeze all her eggs out into a big clutch, within about a minute from start to finish, but sometimes it takes a few minutes longer. There are usually about fifty to one hundred eggs, but sometimes more or less, depending on the size and condition of the female. After the spawning is finished, the female can either leave willingly by herself, or the male will chase her away.

A few links to videos with Ancistrus in the act of spawning:

  • Stephane Loicq - YouTube video:
    ponte d'ancistrus

    Jan 6, 2012
    (The location is next to a filter, in a corner against the glass.
    The act is recorded clearly, so you can see the process with release of milt and eggs.
    This spawning site is not ideal for the male to protect, but it lets us see what is happening.
    With an ordinary type of cave, it is difficult to see much, even with a flashlight.)

  • bungda - YouTube video:
    ancistrus breeding behavior

    Jun 7, 2009
    (The location is in a cave made of a modified flower pot.
    The act is recorded from below, through the glass of a bare bottom aquarium.
    You can see the process with both release of milt and eggs.)

  • TheExAquarist - YouTube video:
    Bristlenose Pleco Ancistrus dolichopterus breeding OR Fish making love

    Apr 15, 2009
    (The location is in a cave made of a modified flower pot tray.
    Filmed in 2001 with night vision DV camera and infra-red light, but recorded on a VHS tape.)
    (I believe this is another species of Ancistrus and not Ancistrus dolichopterus. / Max Standberg)

Eggs, wigglers, fry & parental care:

The eggs usually have a diameter of about three to four millimeters (about 0.10 to 0.15 inches). Very young and/or small females may produce fewer and slightly smaller eggs, while fully grown females in good condition can lay more and slightly bigger eggs. The eggs resemble mustard seeds.

A period of about two or three weeks follows, after the first spawning is finished, when the male guards and fans the eggs, wigglers and fry.

If the yellow eggs turn white over time, it usually means they got corrupted by fungus, but it may perhaps also indicate that the eggs were maybe not properly fertilized, or the brood was perhaps not taken care of properly, or the water quality in the aquarium may not be the best. The male is usually very dedicated to caring for the brood, so I suggest letting him do his thing, as long as he is in good condition. Some breeders prefer to take the brood away from the male.

Some males may choose to spawn with more than one female, making the combined brood even bigger. The exact time it takes for the male to finish guarding the brood varies, mainly due to temperature. A few degrees higher temperature will speed up the process and may shorten the time by a few days. If the male is guarding several batches at the same time, the batches may have been laid on different occasions. Naturally, the time he will need to guard his offspring will be extended, to count for the latest batch.

The male might initially breed with several eager females within a few hours, but he usually doesn't breed with other females again for several days, at least until after all the eggs have hatched. Some males might breed with another female again, when there are wigglers or fry in the cave. However, not all males behave like this. If there is not a surplus of females in the aquarium there will be no opportunity either, since it usually takes almost a month for the exact same female to be refilled with new eggs and become ready to spawn again. If you only have one female and one male in the aquarium, then there will not be a second spawn until after all the fry leave the cave. The same may happen if you have a breeding group of one male and two females, if both females happened to be in sync. The females may spawn with the male, on approximately the same occasion, usually during the same night, since both females need to wait a few weeks until they have developed new eggs, before they are ready to spawn again. However, if they are not in sync, or if there are more females than just two, it gets more complicated.

Some males refuse to let any other fishes, including females of the same species, enter the cave while he is on guard duty. This may include females even if they seem to appear to be eager and ready to spawn. There are a few possible explanations for this, such as the risk that hungry females may raid his cave to eat eggs.

I'm not aware of any reports of female or male bristlenose catfishes eating living wigglers or living fry of their own species. Please contact me and let me know if you have any confirmed knowledge, or maybe even proof, of bristlenose catfishes eating live wigglers, or live fry, of their own species. Please also include a description of any circumstances that may be relevant to the situation. I have heard mentioned that eggs may get eaten by inexperienced males, or by males if they are disturbed a lot, but it may perhaps depend on the strain, or there may have been something wrong with the eggs? The male usually cleans the eggs, prevents and removes mold, and may perhaps remove and eat bad eggs? I think it is uncommon with males eating their own healthy brood.

I'm not sure if males might raid the nests of other males, but they will sometimes try (but usually fail) to occupy the caves of other males. Maybe because they are unsatisfied being without a cave, or may want to upgrade to a better cave, or better location? I suspect there is a small possibility of raiding for eggs, although I cannot confirm this. I suspect some sneaky single males may perhaps also try to sneak in and squirt milt in the cave of a dominant male during a hectic spawn, to perhaps get lucky and fertilize some of the eggs, and then let the dominant male raise the all the fry (that may have either one, or a mix, of the males as the biological father), but I cannot confirm this. It would be interesting if someone captured proof of such behaviors (from bristlenose catfishes) on video?

It is not good to let any females visit inside the cave at the wrong time, especially in case the females are not there to breed, but to raid his precious brood of eggs that he has already invested time and effort into guarding and fanning for several days. Inexperienced or weak males may have trouble keeping hungry females away and may lose some of the eggs on each such raid. There may be differences among individual females if they ever learn to practice such raiding. Some females may perhaps make a habit out of it, or they might never do any raid. It may depend on the male's vigilant protection and perhaps also the size and layout of the cave, if a raider will succeed in the raiding or not.

Link to a video of a female raiding and eating eggs in the cave of an inexperienced male:

As far as I'm aware, the problem with raids by female bristlenose catfishes seems to be about the eggs, but there are many other species of community fishes that may enjoy eating not only eggs, but also wigglers and fry. If the cave is located in a community aquarium, with other fishes big enough to eat the offspring, then the eggs, wigglers and possibly fry, may become food if they are accidentally pushed out of the protected cave.

Another possible reason, and explanation, (for a male not to let females into the cave) could be that some of the eggs, wigglers and fry with yolk sacs risk getting pushed out of the cave by the breeding activity. There seems to be some males that are ok with this risk, and may let females in to breed with him anyway, while other males are not ok with it. It may partially depend on the breeding line, or maybe the origin in the wild, or experience, or a combination of factors? I'm not sure. Another theory would be if a male is temporary out of milt, from spawning recently? I'm not sure how long it takes for a male to be regenerate new milt, or how long milt is viable after being released in the water inside the cave. Does the male use all his milt during a typical night of spawning, or does he leave some milt in reserve?

To prevent accidents in community aquariums, some breeders choose to move the male including his cave and his brood, to another dedicated aquarium, where he can care for his brood in peace, without much disturbance and less dangers to the brood.

During the period with guard duty, the male usually eats almost nothing (compared to how much he usually eats), so it is important that he is in good condition in advance. It is not recommended to let a male breed too many times in a row, making him guard offspring week after week, month after month, without recuperation. Guard duty will drain his body of his body mass and may eventually make him weak and emaciated. If it is a young male, it may also make his growth stunted, if he is occupied with guarding offspring too often, so he may not reach his potential maximum size.

In normal water temperature it takes about five days (from the time of fertilization) for the eggs to start hatching. A newly emerged wiggler has a proportionally huge yolk sac in the beginning. As a wiggler consumes its yolk sac, it slowly transforms into a proper looking fry as the yolk sac shrinks. The fry leaves the cave after it has finished consuming its yolk sac. This is usually a bit over a week from hatching, or about two weeks from the time of fertilization.

If the male has spawned with several females, on different dates, the time table may get a bit confusing with half siblings of different ages mixed together in the cave.

The size of the eggs may vary slightly between females. Some slightly bigger eggs that hatch into wigglers may take a few days longer to fully develop through the wiggler stage, into a fry that have fully consumed their yolk sacs, since their yolk sacs are bigger and takes longer to absorb. Fry originating from big eggs are bigger and more robust, when they finally leave the cave, compared to fry hatching from smaller eggs.

Raising fry:

If the aquarium is filled with "yummy" algae and other aufwuchs, preferably on wood and/or leaf litter, the fry will initially have plenty of food, otherwise you have to hurry and supply food for the fry in other ways. A very young fry does not understand enough about the situation to come out at feeding time, like an older fry does. You may want to catch all the fry and put them in a "fry cage" or a nursery aquarium. If you use half of a coconut shell (or something similarly small) as a cave, then you can shake the fry out, just before they are becoming ready to leave the cave on their own. It can be a lot more difficult to catch the fry once they have already left the cave and dispersed throughout the aquarium. It is a good idea to protect the fry this way, if you have other fishes in the aquarium that want to eat the fry, or if the filter intake is not protected so the fry risk getting sucked into the filter. Another reason to move the fry is if the aquarium is very big and it might be difficult to provide a high enough concentration of food everywhere in the aquarium, for the fry from a single brood to easily find enough food, without fouling the water.

In a fry cage or a nursery aquarium it is easy to feed the fry. Make sure to spread the food around so all young fry can very easily find food. Besides a normal diet (of preferably pureed or powdered versions) of whatever you usually feed your adult bristlenose plecos, I also recommend feeding live and/or frozen nauplii of Artemia (baby brine shrimp, BBS) as a supplement to the fry. Small portions of golden pearls (and other fry food), and finely powdered flake food (preferably vegetable/algae/spirulina flakes), and dissolving food tablets, wafers, cyclops and so on, can also be part of their diet. Very tiny amounts of mashed hardboiled egg yolk (from boiled hen eggs) can be added as a supplement, but will quickly foul the water and become food for bacteria, infusoria and other microorganisms, so only use it in moderation and only if you are able to keep a good water quality.

Remember to try to feed an omnivorous diet, based on plenty of greens (I especially recommend pureed green peas and canned unsalted French cut green beans), with some tiny micro sized and/or pureed meaty foods mixed in. The fry will also feed on infusoria and other microorganisms, that will automatically multiply in the aquarium from feeding on the leftover foods, and juices and microscopic food particles released from the fry foods. Preferably keep some driftwood and/or some leaf litter with the fry.

Try to keep the water quality high and with a high level of oxygen, preferably by using a run through (or drip) water system, connected to a larger aquarium, and/or do frequent small water changes. In short, make sure that the fry cage (or nursery aquarium) is continuously provided good quality fresh water, to keep the water from fouling too much and keeps the ammonia, nitrite and nitrate from becoming toxic, and to keep the bacteria and infusoria within reasonably ok levels. You may want to use snails, shrimps and other species of young fish fry, or very tiny species of adult fish (nano fish), together with the bristlenose catfish fry, to help eat excess infusoria and leftover foods, to balance the eco system. The fry can be housed in the fry cage or nursery aquarium for about a month, before you put them in a larger grow out aquarium. I have raised lots of fry this way.

Related external links & references:

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© Copyright Max Strandberg