Rainbow Shark Medium Epalzeorhynchus frenatus These are very popular freshwater fish. They have other names involving the terms sharkminnow or labeo. Rainbow sharks are bottom feeders and aquarium surface cleaners. Their diet consists of algae, in either tablet or flake form. But, being bottom feeders they can pick up the leftover food. They have been known to be territorial, and violent behavior may occur if they are kept with their own species or relavtives (It is best if they aren't kept with their relatives.) Very compatible with barbs and rainbowfish, because they will stay more towards the top of the tank. Danios and plecos are also stable fish to cohabitate with. Make sure to keep plenty of hiding spaces in the tank, and also allow ample swimming room. The max length of these Rainbow Sharks is usually between 6-7 inches.