The rainbow shark (Epalzeorhynchos frenatum) is a species of Southeast Asian freshwater fish from the family Cyprinidae.

Rainbow sharks are native to the basins of Mekong, Chao Phraya, Xe Bangfai and Maeklong in Indochina.

Compared to females, male rainbow sharks have thinner bodies with black lines along the tailfins.

[3][5][6] It closely resembles "normal" rainbow sharks in temperament and appearance, thus they share the same common names in the aquarium industry.

Being bottom- and mid-level dwellers, they consume leftover fish food, but also eat the algae growing off surfaces.

The provision of hiding places and hollowed decors such as plants or artificial cave-like and tunnel-like aquatic ornaments minimize this typical behavior.

They can be housed with some species of larger freshwater shrimp although any fry or eggs might get eaten by the shark.

They are not compatible with smaller, more timid fish in the tank, as the sharks may terrorize them by chasing them from their territory.

[3][6] Rainbow sharks are picky herbivorous and omnivorous eaters but are primarily consumers of algae in the form of flakes.