Fish breeding is one of the most exciting and interesting aspects of being an aquarium keeper!

Fish keepers start out with a few tropical fish or maybe some gold fish in a small aquarium. But they soon want to know more about how their fish live, and especially how they breed.

General aspects of fish breeding, just like with fish keeping, include proper feeding and providing the right environment. The breeding environment needs to be maintained with proper water conditions and you need to watch for disease or other ailments.

Some fish are easy to breed and will readily spawn in a community tank. But most fish need a bit more help. Understanding the spawning behaviors and needs for the particular type of fish will make fish breeding successful and rewarding.

Carefully selecting the “brood stock” (parent fish) and condition them on a good varied diet is important. A fish breeding tank is needed for many species as well. The breeding aquarium needs to have the right water conditions to stimulate spawning and for the eggs to hatch. Consideration also needs to be given to the fry and their survival. The first foods for the fry, before they become free swimming, and foods for the fry to grow are important. It’s also important that they are protected and have places to hide.

For first timers, or those who are new to the hobby, it’s advisable to start out with some of the easy to breed livebearers. These include the Guppies and Platies. Then move on to some of the hardy egg-layers, like Danios and Barbs. Experience with these initial undertakings will greatly help in keeping and breeding many other types of fish, including some of the very difficult species.

For foods to feed baby fish, see:
Live Fish Foods: Food for Fish Fry

Breeding Anabantoids (Labyrinth Fish)

Most anabantoids, like gouramis and betta fish, are bubble-nest builders. The nest is built and maintained by the male. Male anabantiods will take some time to build a nest of bubbles in floating debris or plants. They entice their mates under the nest and induce them to lay their eggs by giving them a spawning embrace. The eggs are immediately fertilized and placed in the nest by the male who guards them and later, the fry against all intruders.

In the aquarium, an upturned butter dish or something similar can serve as the anchor for the nest. This is usually not necessary though if there are plenty of plants, especially floating plants like hornwort, in the aquarium. The breeding tank is usually small (5 or 10 gallons) and shallow with lots of hiding places for the female (plants and rocks). After the male and female are placed in the tank, the bubble nest is usually built within a few days.

The female can be removed after spawning because the male may become aggressive towards her. The male will then watch over the eggs until they hatch 24 to 30 hours later. The temperature should be about 80° F with a lower temperature extending the hatching time and a higher temperature decreasing it. After hatching, the fry will absorb the yolk sac in two or three days. The fry will not be large enough to eat baby brine shrimp for several days so they must be fed infusoria or cooked egg yolk squeezed through a cloth.

The larger anabantoids are easier to breed mainly because the fry are large enough to eat baby brine or pulverized flake food. For example, dwarf gouramis are harder because the fry are so small they need infusoria to survive the first week or so of life.

Breeding Cichlids

Cichlids fall into several different groupings with different breeding habits. Almost all Cichlids are either “substratum-spawning” or “mouth brooders”. This means they either lay the eggs on some portion of the substratum, (including pits dug in the sand, leaves, and flat rocks), or they take the eggs and fry into their mouths to protect them from predators. Another, and more important distinction, if you are planning to breed Cichlids, is whether they are monogamous or polygamous.

Monogamous cichlids vs Polygamous cichlids:

  • Monogamous cichlids
    Monogamous cichlids pair off when allowed to interact freely in the aquarium. Therefore about six or more young fish should be purchased and grown up in the same tank. As soon as they start pairing off, separate the pairs as they will claim a territory and defend it fiercely.

    Pairs often have trouble because aggression results in a battered female. For this reason many breeders set up barriers in the tank that only the female can pass through thus giving her a safe place away from the male. At the very least a lot of hiding places and maybe a few target fish can be introduced to the pair’s aquarium. The idea is that aggression is taken out on the target fish rather than the female of the pair. Suitable target fish should be fast like giant danios or botias or be able to dive into the gravel like some eels and loaches.
  • Polygamous cichlids
    Polygamous cichlids come in two varieties, open polygamy, where males and females consort freely among each other, and harem polygamy, where males maintain a territory with several females for an extended period of time. Harem polygamy is based on one male protecting several spawning sites from other males. The actual spawning sites are then claimed by each female within the male’s larger territory.

    Females vigorously defend these actual spawning sites. Usually after spawning the male is no longer allowed near the spawning site and the female takes care of the eggs. This type of cichlid is usually marked by extreme sexual dimorphism, with the male being much larger and having more elaborate finnage.

To breed polygamous cichlids, you need a large enough area so that the male has a place to go after spawning so the female won’t batter or kill him. Fortunately most harem polygamy cichlids are dwarfs so a 20 gallon aquarium may be large enough. Overturned clay pots can serve as spawning sites and plenty of plants are always welcome even though prespawning activities may uproot them.

The biggest problem with open polygamy cichlids is that they are thought to form pairs, and being housed this way, the female almost always ends up battered or killed. To avoid this, you can either house them in a community situation with other cichlids (and thus run the risk of producing hybrids) or house a male with at least three or more females. This spreads the abuse out over all the fish which increases their chances of survival.

Almost all the open polygamy cichlids are mouth brooders which means the eggs and fry are carried by the female in her buccal cavity (mouth) until they are free swimming. The substratum spawning cichlids usually excavate pits in the substrate in which to lay their eggs. In both cases the parents will defend the eggs and fry until they are free swimming.

Referenced from Dr. Paul V. Loiselles’ excellent book, The Cichlid Aquarium, Tetra-Press, 1985.

Breeding Goldfish

Goldfish are generally easy to breed!. They are a very social animal and do well when kept in groups. Goldfish typically shoal, forage and feed in groups and are likely to breed in groups as well. It is best to add oxygenating plants such as Anacharis in the aquarium for the spawning process and for eggs to adhere to.

To induce spawning, the temperature can be slowly dropped to around 11° C (60° F ) and then slowly warmed until they spawn. This is done to mimic the conditions found in nature when spring arrives which is the only time they will spawn in the wild. Feeding lots of high protein food such live brine shrimp and worms during this time will also induce spawning.

Before spawning as the temperature increases, the male will chase the female in a non-aggressive way around the aquarium. This can last for several days. The colors of both fish will intensify, the male somewhat more than the female. During spawning the male will push the female against the plants while both fish gyrate from side to side. This stimulates the female to drop tiny eggs which the male will then fertilize. The eggs will stick to the plants by sticky threads. Spawning can last 2 or three hours and can produce up to 10,000 eggs. The parents, when finished will then eat as many eggs as they can find.

For this reason it is best to remove the parents after spawning is complete. You will need to feed one of the various specialty foods for fry (see Foods for Fry) until they become big enough to eat flake or brine shrimp. At first the fry are a dark brown or black color in order to better hide and not be eaten by larger fish. They gain their adult color after several months and can be put in with larger fish once they reach about 1 inch long.

Breeding Killifish

Most species of Killifish are sexually dimorphic. Males are much more colorful than females and will have larger dorsal and anal fins. Having adapted to life in very diverse habitats, the Killifishes are divided into two groups based on different methods of reproduction that they employ. The first group of Killifish are those that are bottom spawners, pushing or burying their eggs in the substrate. The second group are the ‘egg-hangers’, those that usually spawn on plants to which the eggs then adhere.

Killifish are either of the short-lived seasonal or “annual” species or they are of the longer-lived non-annual species.

  • Seasonal or “Annual” Killifish species
    Most surprisingly, some species that spawn on the bottom live a very short ‘seasonal’ life in mud puddles or flood plains. When the mud puddles dry up so do the fish, except for the eggs they left behind buried in the mud. When the rains come again, the next generation of fish is born to repeat this short life cycle.

    Because the entire life span of these fish is no more than 8 months they are considered seasonal or annual fish. In the aquarium they also have a short life span, usually only up to about 1 1/2 years.
  • Non seasonal Killifish species
    These are species that live where there is always water. Most will spawn on plants though there are a few species that spawn on the bottom. They produce eggs that will adhere to the plants. These fish are longer living in the wild, usually 3 to 4 years.

    Many non-seasonal types of Killifish have a lifespan of 5 or more years in the aquarium

Breeding Livebearer Fish

Livebearers are generally very easy to breed. Like most other fish, the hard part is raising the fry. Generally the parents and other fish in the tank become predators to newly hatched fry but there are several solutions to this problem.

The easiest solution to predation is to provide good cover and hiding places for the fry in the form of plant cover like anacharis* and hornwort*. This will help but some will still get eaten. Another solution is to buy a breeding net, which provides a separate compartment in the aquarium for the mother before she drops the fry. After dropping the fry the mother can be removed so the fry are separated from the rest of the tank by the breeding net. Along the same lines the mother and fry can be placed in a separate aquarium so the mother can be separated from the fry when they are born. Breeding traps are also utilized which keep the mother confined with a grating that the fry can pass through.

The fry can be fed baby brine shrimp, which is usually purchased frozen, or can be hatched from brine shrimp eggs. Also pulverized flake food, which is sold as baby fish food, and hardboiled egg yolk strained through a cloth.

Breeding Catfish

There are many catfish species, but not all are successfully bred in the aquarium. There has been good success with the Coryadoras, but species like the Plecostomus simply require a large pond with mud banks for them to dig spawning areas. Their requirements just can’t be accomodated in home aquariums.

  • Breeding Corys (Armored Catfish)
    Suggested water conditions for breeding: pH: 6.0-6.5, hardness: 4? dGH. To prepare a pair for breeding set up a tank with large leafed plants. Feed the pair plenty of mosquito larvae and other live foods. Spawning is stimulated with frequent water changes.

    The Corys have a very interesting breeding routine. After bumping the male on the vent, the female will receive the males sperm into her mouth. She then discharges a few eggs which she catches and clasps with her ventral fins. Then the female will swim around and deposit a bit of sperm and just a few eggs at a time in select spots, such as on the underside of a selected leaf, some will deposit them on the heater tube or ever the aquarium glass.

    When the female runs out of sperm, she will go back to the male and repeat the process until the spawn is complete.This will continue until about 100 eggs are deposited. Different species will put different amount of eggs on each leaf or other selected spots. After spawning the pair should be separated from the eggs. The eggs should be well aerated and treated to prevent fungus form growing on the eggs.

    The fry will hatch after four or five days and can be fed rotifers, Artemia, nauplii, and the contents of fresh peas.

Breeding Characins (Egglayers)

Characins all breed the same, with just a few exceptions. Characins such as Tetras, Silver Dollars, Hatchetfish, Headstanders, and Leporinus are free spawning. This means they will discharge the eggs and sperm into the open water, though always around bushy planted areas.

It is best to spawn most characins by separating the males and females and then feeding them heavily on live foods until the females grow fat and the males become more colorful. Then introduce a female and a male into a specially prepared spawning tank.

The spawning tank can be a low aquarium (5 gallons to 20 gallons depending on the species) filled 3/4 full with clean, aged water and lined with a dense foliage about two inches thick. The Glowlight Tetra is an exception here, in that they don’t like the vegetation dense. You do not need any sand on the bottom but you can add a few pieces of wood or twigs with free space underneath to give the fry a place to attach. For the Neon Tetras, it is recommended that everything you place in the aquarium be sterilized, as well as the top. Other characins do not seem to need quite as much care to spawn successfully.

Usually an increase in temperature to about 78? F (see individual species), feeding plenty of live foods, and covering the aquarium with a towel (to darken it and maintain temperature) will trigger spawning. Spawning usually takes place in 48 hours to a few days. The eggs of most characins are quite sticky and will then adhere to the foliage as they are dropped. Remove the parents as soon as they have completed spawning or the parents might eat the eggs.

The spawning aquarium temperature can then be increased to and maintained at about 80? F . The eggs hatch quickly, usually in about 36 hours. The fry need to be fed infusoria, especially rotifers, for 1 to 4 weeks, depending on the species. Then they can eat brine shrimp.

The Congo Tetra is another exception here in that they spawn in temperatures of 77? F , and their eggs take 6 days to hatch.

Breeding Cyprinids (Egglayers)

Most Cyprinids are free spawning. This means they will discharge the eggs and sperm into the open water. Cyprinids include Barbs, Danios, Rasbora, Chinese Algae Eater, Bala Shark, Red-tailed Sharks and Black-tailed sharks, to name a few.

With Cyprinids, usually an increase in temperature and feeding plenty of live foods will trigger spawning. The eggs will then adhere to whatever they come in contact with: leaves, decorations, gravel, etc. The eggs hatch quickly, usually within 30 hours at which time the fry can eat finely powdered flake food followed by baby brine shrimp after a week or so.

The parents will eat the eggs and the fry so some means of protecting the eggs is needed. To accomplish this you can use spawning grass, marbles in the bottom of the aquarium, or a grating that the eggs can fall through but the parents cannot. After spawning it is a good idea to remove the parents.

One of the notable exceptions to this method of breeding is the practice of the Bitterling, Rhodeus sericeus amarus, who protects the eggs within the Mussel and defends them after they have hatched

Breeding Rainbowfish (Egglayers)

Rainbowfish spawn year round in their native habitat, and are easy to breed in captivity. Not only are Rainbowfish easy to breed, but their fry are not difficult to rear. Australia has strong restrictions on the exportation of live animals, so many of the Rainbowfish species that have become available were the result of eggs being airmailed to Europe and the United States. where they were hatched and the fry reared.

Rainbowfish have been found to breed most readily in the aquarium, especially after a water change. They will often even spawn in a community tank, but other fish and young rainbowfish will snack on the eggs. A breeding tank should be three or more feet long with aged water that is the same temperature as the species tank or a few degrees warmer. Use a thin layer of gravel or shell grit as a bottom substrate. The tank also needs to have a filter or be aerated. Provide either fine plants or an artificial spawning substrate for the eggs to adhere to and the hatched fry to hide in.

Introduce either a pair at a time or three male Rainbowfish of a similar size with two females. The male of most species will display a bright courtship stripe. The males will court the females by swimming around their partner in circles while displaying. They will also do a headstand, indicating (pointing to) the spawning site. A receptive female will follow the male to the site where the two will swim closely side by side. The fishes’ bodies and fins will vibrate for a few seconds as the sperm and eggs are released. Then they will quickly dart away, creating a whirling of the eggs and sperm.

After a spawn there can be from two to over 200 eggs. They each have a long thin thread which attaches the egg to the spawning substrate. The larvae hatch in 4-14 days, depending on the species and the temperature. They should be feed very tiny foods often, at least twice a day. Beginning foods can be commercial prepared fry foods, finely ground flakes, infusoria, and nauplii. They grow quickly and will soon be able to take larger sized foods. They will be fully grown in just a few months, but it takes two to three years for them to reach maturity.

A problem to be aware of is crossbreeding. Rainbowfish in the wild will not breed with fish of another species, even when presented the opportunity to do so. But for some reason, rainbowfish of the Melanotaeniidae family in the aquarium will interbreed, often with undesirable results. Somehow the fry of mismatched parents lose most of their coloration. Since many of these species are rare, it is desirable to keep the bloodlines distinct, or risk losing the beautiful coloration that nature has taken thousands of years to develop.

Breeding Perches – Archerfish

The archer fish have been bred in Australia by a commercial fish farm, Ausyfish Pty Ltd, according to Bruce Sambell commenting on the Archerfish page. According to Bruce they were spawned with hormone. About 10,000 eggs hatched. They were a variety which is strictly freshwater! Thanks goes to Bruce Sambell for this fascinating information and an introduction to his fish farm Ausyfish Pty Ltd.

Spawning Information:

  • Brood fish were collected from upper reaches in pure freshwater on Cape York, Queensland.
  • Fish were injected the first week of February 2007 after a “running” male was detected.
  • No obvious external sex differences. ·The female had a slightly enlarged abdomen but virtually no different to the running male.
  • Injected the fish with hormone at standard rate. (1 pair)
  • Male weight 145gms, Female weight 261gms
  • Water was maintained at 25C
  • PH 7.8
  • Larvae were pigmented.
  • From above the larvae appeared as bright white specks. From the side they appeared dark in colour. Under magnification, they looked like miniature version of the adult fish.
  • Larvae were fed newly hatched artemia.
  • After 7 days of feeding artemia, they were gradually converted to dried feeds.
  • Larvae grew very quickly at high temperatures but slowed dramatically when temperatures dropped. At 3 months old, tank raised larvae were 30mm. At 6 months old they were still 30mm
  • At 6 months old pond raised larvae had reached 13cm.