Dozens of species of rainbow fish live across different habitats. Rainbow fish make up taxonomic family Melanotaeniidae. These fish often have bright coloration and interesting schooling behavior. Their range includes at least two continents and dozens of islands. To keep them at their best in captivity, you must understand their preferred habitat and replicate it in the home aquarium.
Where in the World
Rainbow fish live in Madagascar, New Guinea, and parts of Indonesia and Australia. In Australia, they live in the northern and eastern part of the continent. However, individual species of rainbow fish have more restricted ranges. The Celebes rainbow fish lives only on a single island, Sulawesi, formally known as Celebes. Other species have home ranges that are even more limited. For example, the Lake Kutubu rainbow fish originates in a single lake -- you may have guessed which one -- in New Guinea.
Since the family of fish lives across such a huge range, many of the specifics of their habitats vary wildly from species to species. Different types of rainbow fish have adapted to lakes, rivers and estuaries. This means that some species live in pure freshwater while other can tolerate some salinity in brackish habitats. However, their habitats generally have a few things in common. First, rainbow fish generally come from clear, clean water. Additionally, most species tend to congregate in dense vegetation for protection. And all rainbow fish live in the tropics, where water generally is warm.
Recreating Rainbows' Habitat
In the home aquarium, you need to mimic certain elements of rainbow fish's habitat to see them at their best. They generally need lots of swimming room, since they swim actively. Smaller species need an aquarium of at least 20 gallons, while larger species generally need a minimum aquarium size of 30 gallons to thrive. The decor should consist of open swimming areas and heavily planted thickets. The thickets help rainbow fish feel secure. You need to research the particular species you keep -- some species of rainbow fish need a little aquarium salt in their water and other don't. Tropical conditions between 70 and 75 degrees Fahrenheit will accommodate most species.
Caring for Rainbows
In addition to their aquarium setup, you need to provide care that mimics conditions in the wild. Always keep rainbow fish in groups of at least six. In the wild, rainbow fish school for protection. In captivity, they get stressed when they're on their own. Throughout their habitat, rainbow fish eat a variety of foods, making them pretty easygoing omnivores in captivity. You will see their best coloration if you feed live and frozen foods like mosquito larva, Daphnia and bloodworm.
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