Capillaria catenata is a a nematode parasitizing the intestine of freshwater fishes. It was described from Lepomis gibbosus in Lake Oneida NY in 1932. It has been reported from 21 species of freshwater fishes, of many families, although fishes of the families Centrarchidae and Percidae appear to be the most common hosts. It appears to have a wide native range in Eastern North America, from Quebec to Wisconsin, south to Georgia and Arkansas. Occurrences in Idaho, Montana, and Wyoming probably result from the stocking of game-fishes. In 1973, it was found in the intestine of Cyprinus carpio (Common Carp) collected at the Tracy pumping station in the Sacramento-San Joaquin Delta.