Percopsidae is a family within the order Percopsiformes. It is composed of two North American Fresh water species, trout-perch Percopsis omiscomaycus (Walbaum 1792) and sand roller Percopsis transmontana (Eigenmann & Eigenmann 1892).
Trout-perch
Trout perch are silvery-transparent in appearance. Specimens found in the US range from 76-102 mm while ones found in Canada can get as big as 152 mm. These fish live 3-4 years in shallow lakes and streams, hiding among among rocks. They survive on chironomids, ephemeropterans, amphipods, and small fish.
Sand roller
Similar in appearance to trout-perch, although shorter and stubbier, sand rollers grow up to 9.6 cm and live up to 6 years in slow-moving, sandy-bottomed streams and rivers among vegetation. Their diet includes Diptera and Trichoptera, although juveniles also have been known to eat crustacean zooplankton.