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 &
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 with 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.
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
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.
Mulm in the aquarium may also 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.
Mulm may also become like a factory for microorganisms, that the bristlenose catfishes can eat as biofilm.
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 biofilm 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.
Perhaps mud may play some role in digestion?
However, there are many aquarists that manage to keep bristlenose catfishes successfully in bare bottomed aquariums.
Substrate seems to be optional, some breeders use sand or gravel, but bare bottomed is just as common.
I can only speculate, but mud may or may not play a role 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.
Other animals have adapted to ingests mud to help with digestion in different ways.
I don't know if bristlenose catfishes may benefit from mud or not.
It may depend on what type of mud it is and how it is used.
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 of the most popular leaves to use as leaf litter, among aquarists, are oak leaves and Indian almond leaves (catappa leaves).
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 other 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
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 also can 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, it is recommended to slightly increase the protein content in the 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 also eat some (but not all) types of algae and biofilm in your aquarium.
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 other biofilm may add to either the carnivorous part, or the herbivorous part, of their omnivorous diet.
There is a difference if you only have one, or a few, individuals 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 to compensate for this.
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,
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 good chance of being usable.
If you want to risk using use them, I suggest careful rinsing + blanching/boiling and/or peeling them before usage.
Be aware that there are scammers who make false claims about their products,
so if you do not trust the seller completeley, then it is preferable do 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.
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,
- 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 ),
copepods, amphipods (scuds/gammarus 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:
(bok choy, pac choi),
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 works, but is less convenient for fishes to graze on.)
- Preferably without added salt.
(Salted usually also work, but be careful.)
- Canned green beans have a soft texture compared to raw and frozen green beans.
(Bristlenose catfishes enjoy this texture.)
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
For feeding bristlenose catfishes, one of the most commonly used
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 pumkin 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 and other living organisms in your aquarium,
but I think it is better not to test it.
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 it.
More about feeding vegetables, root vegetables and
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.
Some 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.
Dry, fresh, blanched or boiled mulberry leaves 🌿 are recommended.
Both bristlenose catfishes and most types of freshwater shrimp 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, unless it is from a stinging/poisonous weed, fresh young tender leaves are good to use raw.
If you want to use older tougher leaves, or make the food easier to chew and digest, then blanched or 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.
In its peak season, nettle contains up to 25% protein,
dry weight, which is high for a leafy green vegetable.
- 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.
Algae foods & dietary 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
- 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.)
Wafers, pellets, granules, tablets, vibra bites and flakes:
There are many types of dry foods in aquarium shops that are made for plecos and other fishes with similar dietary needs.
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.
Some people like to keep snails together with bristlenose catfishes.
Be aware that some 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 or rot if left too long, especially if there is gravel in the aquarium.
Food particles may fall down among the gravel and burrowing snails may have a much easier time to 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.
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.
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.
I also recommend the documentary THE AMAZON RIVER OF THE SUN (Equator S1, Ep3, from 2009), also known as Rivers of the Sun.
Narrated by Peter Hayden and directed by Shinichi Murata.
This documentary aired on TV, but is also sold on Blu-ray and DVD.
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 recommended,
but common bristlenose catfishes tolerate a few degrees lower and higher, assuming all other water parameters are ok.
However, more extreme temperatures will start to affect breeding behavior, 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, which is an adaptation they have,
to temporarily survive low oxygen conditions.
Investigate and fix the problem as soon as possible if you notice such behavior.
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:
The male bristlenose catfishes can grow to about fifteen cm (about six inches)
and the females can grow to about twelve cm (about five inches).
Those 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.
The males get soft outgrowths on their heads, that look like deer antlers or tentacles.
These soft outgrowths are missing or occur very sparsely among the females.
I suggest to avoid using females with soft outgrowths for breeding, especially if you can get another female without them instead.
Even if the soft outgrowths are small, it is not a trait normal aquarium keepers and aquarists in general want to enhance in
Ancistrus females 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 a broad head.
It is generally preferred if the gender differences are kept as clear as possible through the generations, so people can easier tell the difference.
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 can also 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 soon 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 one or several times 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 soft outgrowths are not odontodes! Many people, including reputable aquarists,
have unfortunately often called them odontodes, but this is a wide spread misconception, a common mistake.
Bristlenose catfishes have cheek odontodes on each side of their heads.
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.
Cheek odontodes and the pectoral-fin spine odontodes can often be helpful when determining the gender
of various different species of armored catfishes.
Odontodes are also called
They have a hard outer structure, but a soft inner structure, similar to how teeth are constructed.
On each side of their heads, located below their eyes, bristlenose catfishes have hard sharp cheek odontodes,
that they can fold inwards, to normally keep them mostly hidden, or flex them outwards from their head (in a scary way) when they want 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 as curved.
However, some (but not all) species of Lasiancistrus 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 usually stay erected and they also spread out their pectoral fins.
As the bristlenose catfishes grow older, the cheek odontodes get bigger. Males get bigger cheek odontodes than the females.
When two males of similar dominance levels fight, their cheek odontodes 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.
Usually, it ends up with more fights if there are not enough caves.
Fights, 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 fighting:
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, or a pillowcase 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 use 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.
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.
Spawning caves, spawning preparations & in the act of spawning:
The male bristlenose catfish will choose a favorite cave in the aquarium.
It is preferable if there is only one entrance.
If it is a tube, then you should either plug or cap one end, 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 to a future brood,
to prevent invaders from entering while he is tending to his brood.
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 metal file, and/or some 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:
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,
and spawn with the male about 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 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.
If the aquarium is filled with "yummy" algae and other
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.