Breeding rainbow fish

Breeding rainbow fish

What you will need

  • colourful male boesmans rainbow fish
    Male boesmans rainbow fish showing full breeding colours

    2 foot tank hood and light perhaps 3 ft for bigger species

  • sandy bed
  • fine plumed plants across back and sides
  • several java moss tufts
  • 2 sponge filters powered by an air pump

General care and information

When bought they are quite drab juveniles and may take up to a year to show their full adult colouration. So be patient. The boesmans rainbow fish can grow to 4 inches. They need a varied diet of live food, vegetation and dried foods to bring out the full colours of the rainbow fish.
They are usually easy to breed. The males are bigger, have a deeper body and are more colourful than the females. Rainbow fish are not aggressive and are ideal for a community aquarium. They are a shoaling fish so you need at least 6 in the aquarium. Therefore raise them in a large community aquarium of at least 4 foot. Include an open swimming space in the front of the aquarium. Temperature should be at 76F. Boesmans rainbow fish should have a higher temperature of 83F and the ph of 7.4 or possibly higher and hardness of 20dh. For other rainbow fish the water should have a hardness reading of 15dh and ph about 6.3 but this is not absolutely critical.

Preperation for breeding

Regular water changes are essential of 25% per week with aged water. Feed well with live food and quality dry food. Place a single pair in the breeding pair. Pick out a pair who have previously shown some interest in each other. The female should look plumper and the male should look more colourful.


pair rainbow fish spawning
breeding pair of boesmans rainbow fish spawning on plants

He darts to the spawning area and back to the female several times until she follows him. When she goes to the spawning area the male follows her. This is where she will lay her eggs to be fertilised by the male. There seems to be several practice runs. The male is by far the more active partner. Spawning usually occurs in the morning. The female swims between plants and over plants laying eggs which are fertilised by the pursuing male. The eggs remain attached to the plants by thin sticky threads. The female lays between 20 and 60 eggs. They eggs can be removed to a raising tank using some water from the breeding tank. However, it is best to remove the adults. Rainbow fish don’t usually eat the eggs or young as long as they are well fed.

Raising the young

Remove the parents as soon as spawning has finished because they are avid egg eaters.
After 5 to 11 days depending on species, the eggs hatch. After a further 5-7 days the fry become free swimming and can be fed with brine shrimp and daphnia. Do not feed the fry with any foods that sink. The fry stay mostly near the surface.

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