The mud sunfish (Acantharchus pomotis) is a freshwater ray-finned fish, a sunfish from the family Centrarchidae, which widely distributed in the fresh waters along the Atlantic coast of North America, ranging from New York to Alabama. It is the only species in the genus Acantharchus.
Taxonomy
The mud sunfish was first formally described as Centrarchus pomotis by Spencer Fullerton Baird in 1855 with the type locality given as Cedar Swamp Creek in, Beesley's Point, New Jersey and the Hackensack River in Rockland County, New York. In 1864, Theodore Nicholas Gill placed it in its own monospecific genus Acantharchus, the new genus name being a compound of the Greek words meaning "thorn" and meaning "anus". This species has rounded pectoral and caudal fins. They can grow to a maximum total length of , although is a more common total length. Its range has also significantly reduced in New Jersey, particularly in the northern and central parts of the state but it remains reasonable common and widespread in the Pinelands. In New Jersey the fish's decline is possibly a result of a number of reasons including land use and habitat changes and the introduction of non-native fish which predate on the mud sunfish and in this state it has been recommended that it be classified as a species of special concern. It has been extirpated from Pennsylvania.