Fishes That Care For Their Offspring


These are some of the most interesting types of fishes to breed in my opinion. The fishes have evolved many different ways of caring for their young. Sometimes it's the male, sometimes the female and sometimes both parents that take part in caring for their own offspring. Sometimes even the offspring of other individals of the same species, or the offspring of parasitic species can also be cared for.

Side note:
The embedded links inside this article point to the corresponding webpages in english at Wikipedia, except for links with the names of other websites stated in the links.

Some different ways of caring for the offspring:

Ex 1. Bubble nest builders, also known as aphrophils:

The eggs and newly hatched fry are usually guarded and tended to in the nest by only the male in most bubble nest builders. (Some snakeheads can also have the female participate.) Examples of common bubble nest builders in the aquarium hobby:

Ex 2. Mouthbrooder, oral incubation:

I am mainly refering to ovophile mouthbrooding (also called immediate mouthbrooding), when all the eggs are immediately stored in the mouth of just one parent during the spawning. After the fry hatch the parent continues the mouthbrooding and holds the fry in the mouth until the young can take care of themselves. Sometimes the fry get to temporarily leave the mouth of the parent, but are soon taken back inside the mouth again whenever the parent calls them back. The act of mouthbrooding is is also called "holding". It refers to holding incubating eggs, wigglers (fry larvae) or free swimming fry in the mouth.

When only the female is doing the mouthbrooding it is called maternal mouthbrooding.

When only the male is doing the mouthbrooding it is called paternal mouthbrooding.

When both the male and the female share responsibility and take turns doing the mouthbrooding it is called biparental mouthbrooding, but biparental mouthbrooding behaviour is very rare.

There are also larvophile mouthbrooders. They lay eggs in the open or in a cave, but don't incubate the eggs in the mouth. Instead they wait until after the eggs have hatched and only then put the wigglers, and later free swimming fry, into the mouth.

Examples of ovophile mouthbrooders in the aquarum trade:

  • Males of: Silver arowana (Osteoglossum bicirrhosum)

  • Females of: Australian arowana (Scleropages jardinii)

  • Females of many different species of cichlids in Africa. It is especially common among many of the popular cichlids in the aquarium hobby such as Cyphotilapia, Maylandia, Pseudotropheus, Tropheus etc. Most of the popular ovophile mouthbrooding cichlids originate from the lakes in Great Rift Valley in East Africa, such as Lake Malawi, Lake Tanganyka and Lake Victoria. There are also some cichlids that are ovophile maternal mouthbrooders in rivers and other lakes in Africa.

  • There are only a few cichlids from South America that are ovophile maternal moutbrooders, such as: Redhump eartheater (Geophagus steindachneri)

  • A monogamous biparental mouthbrooding cichlid from Lake Tanganyka:
    Tanganyika Clown (Eretmodus cyanostictus)
  • Males of: Mouthbrooding fightingfish (Betta pugnax)
  • Males of: Banggai cardinalfish (Pterapogon kauderni)

Ex 3. To lay sticky eggs in a single location openly.

Both parents usually guard and clean the eggs. The eggs stick almost like glue to whatever they were laid on, usually leaves, stones or tree roots in the wild. In aquariums the eggs can often also be laid on flowerpots, glass walls, algae magnets, spawning cones or filters etc. After the fry have hatched the parents continue to care for the wigglers and later also the free swimming fry, until the fry can take care of themselves. In freshwater this is mainly done by many species of cichlids.

The parents may use their mouths to tend the eggs, wigglers and fry. They may clean the eggs and remove dead ones. They may also pick up one or a few newly hatched wigglers at a time with their mouths and spit them back among the eggs, or they may move the wigglers to a new location, often a small pit dug by the parents. The parents may also collect straggling fry and spit them back into the main brood, but the parents do not usually incubate the eggs in the mouth, like oral incubators do. Although it is not oral incubation, the use of the mouth to tend to the brood is often refered to as a form of mouthbrooding by biologists, however unlike biologists most aquarists instead reserve the term mouthbrooding only for the oral incubators, to avoid confusion.

When the fry get free swimming they will learn to follow their parents. The parents herd the fry around. The parents often use interesting body language and behaviors during this time. Usually the parents also change to a different colortone during the herding of the fry, so the fry can more easily learn to recognice the parents.

A few especially adapted cichlids (Symphysodon sp. and Uaru sp.) also nurse their young by providing them with their parental slimecoat as food for the fry to eat and grow faster.

Ex 4. To lay the eggs above the water!

The male splashing tetra (Copella arnoldi) splashes water on the eggs that have been laid and fertilized above the water under a leaf, root, aquarium glass cover etc. The male does this until the eggs hatch and the fry fall down and swim away.

Ex 5. To lay the eggs hidden inside caves, shells etc.

This is done by many plecos and also many dwarf cichlids.

The dwarf cichlid males sometimes have a harem with females. Then it's usually the females that guard the offspring while the male defends a larger terriotory. In some species both parents help to guard the eggs and fry until they can take care of themselves, even after the fry have initially left the cave or shell.

The different species of plecos that are cavespawners only guard their offspring until the fry have consumed their yolk sacs and leave the cave, but this can take weeks of guard duty, so the fry are usually fairly large by the point they finally leave the cave and start foraging for food.

Ex 6. To act as a parasite or a symbiont:

For example cuckoo catfish (Synodontis multipunctatus and Synodontis grandiops) that can use mouthbrooding cichlids to guard their catfish eggs and catfish fry, while the eggs and fry of the cichlids get eaten by the catfish fry. The bitterling (Rhodeus sericeus) lay their eggs in a living freshwater mussel (Unio pictorum). In the mussel the offspring is well protected until they get freeswimming and leave the mussel. An other example are clownfishes and sea anemones. In the wild the different species of clownfish have symbiotic relationships with a few specific species of sea anemones and they have adapted to eachother. A pair of clownfish spawn very close to the base of the anemone, where the eggs get partial protection while they are being tended to by the pair of clownfish.

Links about breeding behavior in cichlids:

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