Rainbowfish are small colorful fish that are very suitable for freshwater aquariums. They originate from Australia and New Guinea and a few other islands in the area. They are easy to keep and can be recommended to even the beginning aquarist.
Rainbowfish are from the family Melanotaeniidae. The family name is derived from the ancient Greek words “melano” which means black and “taenia” which means ribbon. This is appropriate for the genus Melanotaenia because species within that genus have black markings on their dorsal and anal fins. Other popular genera within the family include Glossolepis and Pseudomugil (Blue Eyes).
They are a relatively small tropical fish so they do not need a large aquarium and they will not harm live plants. They are active swimmers so the horizontal dimensions of the tank are more important than the vertical ones and there should be lots of open space. Since size varies from species to species, you should research your particular species (as always) before purchasing.
Generally rainbowfish come from very soft water so you may have to do some adjustments if your water is particularly hard. Generally speaking they can live in water with a pH between 6 and 9, but as always it is better to avoid the extremes. Water temperature should be between 75 F (24 C) and 82 F (28 C) with the higher temperatures being recommended for spawning and raising fry.
Rainbowfish are omnivores and will eat practically anything. Ideally their diet should be approximately 60% plant/algae based and 40% protein based. Natural algae in your tank is an ideal food source. You can also provide vegetables such as boiled peas, pumpkin and zucchini. Feedings of mosquito larva, fruit flies, etc should be used to provide the protein. Avoid fatty foods such as beef heart.
Rainbowfish are occasionally found in aquarium stores, but in my experience the best place to find them is either at your local aquarium club auctions or on-line.
I hope this brief summary has sparked your interest in this great group of fish. Please leave your comments below.