The Zebrafish is one of the hardiest and most active schooling fish for the upper levels of the aquarium. I acquired a small group to attempt breeding, including both the standard and long-finned varieties, to see the results of crossing these two types. Originally from South Asia (India and Pakistan), they inhabit everything from streams to rice paddies.
Beyond being a popular aquarium fish, Danio rerio is world-renowned as a model organism in scientific research, as its genome is surprisingly similar to that of humans. In the aquarium, they require plenty of open swimming space due to their extreme speed and constant movement. They should always be kept in a school of at least 6-8 individuals to thrive.
Breeding
It is often said that Danio rerio and its spotted morph Danio 'frankei' are some of the easiest fish to breed. They are classic egg scatterers, releasing eggs freely into the water column or over fine-leaved substrates like Java moss. Because they are notorious egg eaters, it is necessary to use a breeding trap or a thick layer of glass marbles at the bottom of a separate breeding tank so the parents cannot reach the newly laid eggs.
