Breeding Freshwater Fish
| Contents |
Dr.
Jungle recommends...
Guppies,
Mollies, Platys and Other Live-Bearers
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Anabantoids
(Labyrinth Fish):
Bettas, Gouramis
Catfish
~ Cichlids ~ Goldfish
Characins:
Tetras, Silver Dollar, Hatchetfish, Headstander, Leporinus
Livebearers:
Mollies, Guppies, Platys, Swordtails
Cyprinids:
Barbs, Danios, Chinese Algae Eaters, Rasboras, Bala Sharks, Black-tailed
Sharks and more
Rainbowfish:
Live Foods ~ Food
for Fish Fry
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Buy
it here!
Goldfish Breeding and Genetics |
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Anabantoids
(Labyrinth Fish)
Most anabantoids 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.
Cichlids
There are several different groupings that Cichlids fall
into concerning breeding habits. Almost all the 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.
The material here is taken mostly from
Dr. Paul V. Loiselles' excellent book The
Cichlid Aquarium,
published by Tetra Press, 1985
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 pairs' 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 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 such cichlids, you therefore 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.
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 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.
Livebearers
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 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.
Catfish
*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.
Characins
(Egglayers)
Characins, which includes 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.
Characins all breed the same, with just a few exceptions.
It is best to spawn them 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.
Cyprinids
(Egglayers)
Most Cyprinids, which includes Barbs, Danios, Rasbora,
and Black-tailed sharks, are free spawning. This means they will discharge
the eggs and sperm into the open water.
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
Rainbowfish (Egglayers)
Rainbowfish spawn year round in their native habitat, and are easy to breed in captivity!
Fortunately Rainbowfish are easy to breed and 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
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