Easy to keep than many tropical fish. Rainbow fish comes from the tropical southern hemisphere, mainly from the waters around Australia but also parts Southeast Asia. It belongs to the Melanotaeniidae subfamily and its size can vary wildly, depending on the subspecies.
The largest types can grow up to 9″ (20 cm) in length, and the smallest can be less than 1.5″ (3 cm) long. The best way to keep this colorful fish is to have groups of 10 to 15 individuals together. Always have a minimum of six individuals together in a group.
As rainbowfish swim near the surface of the water, you do not need a deep aquarium and the length of the space is more important. They also like to have some room for swimming around, and as these playful fishes like to jump out of the water you should be able to close your tank.
If you want your fish to spawn, rainbow fish is a good choice. Most of the time it is easy to tell the males from the females, as the male color is more vibrant. Some species like to spawn in pairs and some in bigger groups, usually two or three females for every male. The best way to enjoy the bright colors is to have several males together, because they develop their shine in order to attract the females.
You can also set up a smaller aquarium specifically for breeding. The best water temperature for breeding is between 24 and 28°C and the pH should be on the alkaline side of neutral. Rainbowfish can lay eggs daily during the breeding period, but they are famous for eating the eggs so it is best to remove the eggs and keep them in a separate container. Hatching takes between 6 and 9 days. The baby fish can be first fed with liquid fry food or infusoria, and as they grow, you can start to add newly hatched brine shrimp.
Compatible: Tetras, Rasboras, Danios, Dwarf Gouramis, Livebearers, Corydoras, Discus, Angels, Barbs, Rainbowfish, Plecos, and Scavenger Catfish of similar size. Aquarium setup: 72-77°F; pH 65-7.2; dH 10-15