The rainbow shark (Epalzeorhynchos frenatum) is a species of Southeast Asian freshwater fish from the family Cyprinidae. It is also known as the ruby shark, red-fin shark, red-finned shark, rainbow sharkminnow, green fringelip labeo, whitefin shark and whitetail sharkminnow. It is a popular, semi-aggressive aquarium fish. Unlike true sharks, which belong to the Chondrichthyes ('cartilagenous fishes') lineage, the rainbow shark is an actinopterygiian ('ray-finned fish'). The rainbow shark has an elongated black, dark blue or bright blue body. The snout is pointed. The abdominal area is flat. The fins possess red to orange-red coloration. The linear area from the gill cover, the eye, and the mouth has a characteristic brief stripe. Compared to females, male rainbow sharks have thinner bodies with black lines along the tailfins. Males also have brighter coloration. They can grow up to about 6 in (15 cm) long. (Source: Wikipedia.org, CC BY-SA)