Blue chromis (Chromis cyaneus) are from the Caribbean and the West Atlantic. They belong to the family Pomacentridae. They are part of a group of fishes commonly known as damselfishes.
They are brightly colored, very active, small fish, reaching an adult size of only 4-5 inches or 10-13 cm. They are shoaling fish and so you should keep them in small groups of 6-8. A solitary chromis usually doesn't survive.
In their natural environment blue chromis are typically found within shallow coral reefs and are usually in groups. For the most part they get along fine with one another in the aquarium. They are mostly peaceful fish and should be kept with other peaceful fish of similar size. It is a good idea to provide plenty of live rock in your tank for hiding places, although blue chromis typically spend most of their time out in the open. They can be kept in a reef tank.
They are omnivores, meaning that they eat both meaty and plant based foods. They are not difficult to feed and will eat a variety of regular aquarium fare, frozen, live, and sometimes even dry food. Feeding them a variety of foods will help them retain their color in captivity. They sometimes feed on the algae in the tank.
They have been known to spawn in captivity.
Blue chromis can usually be obtained for about $10-15.