The pirate perch is the only species in this family. It is a small fish typical of slow-water, weedy habitats. It is characterized by a single dorsal fin with both spines and rays, rough scales over its entire body, and its most distinctive feature, its anus below its opercula. In New York it is found in two areas: tributaries to the Great Lakes and on Long Island. Individuals are sufficiently different in appearance to be treated as subspecies and both subspecies are native to the state. The western form is rare.