Definition: Fry tanks are important when trying to successfully raise fry after spawning breeder pairs. Often the breeding tank will be the same as the grow-out aquarium. After the fish have spawned and fertilized the eggs, or in the case of livebearers, dropped their babies; the parents can be moved to the main tank to allow the fry to grow out. This is important to ensure that the fry have a safe place to develop until they are able to take care of themselves.


Larger fish, even if they are the parents of the fry, will usually eat the small fish. Another hazard is the filter. Usually the filtration for a fry aquarium is different than the main aquarium, as young fry are not able to swim away from a strong filter intake. The most popular filter for raising fry is the sponge filter. Although it does not offer powerful filtration, the gentle suction at the outside of the sponge will not cause a problem even for the feeblest of swimmers. When several of them are used in the fry tank, one can be regularly cleaned to remove trapped debris while the other can be left to become strongly biological and even grow a collection of rotifers to be used as a small addition of live food in for the growing fry.