Mud sunfish
(Acantharchus pomotis)

The mud sunfish (Acantharchus pomotis) is a freshwater ray-finned fish, a sunfish from the family Centrarchidae, 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.

The mud sunfish is a small fish that can be distinguished from other members of its family by its possession of 5 or more spines in its anal fin, by having less than 15 gill rakers, and in being the only species in its family that has cycloid scales. Its body is oblong and compressed with a large mouth and eyes. This species has rounded pectoral and caudal fins that are clear through to dark olive in color and the anal fin has a black margin. It has a dark spot on the gill cover and the color of its body varies from brown on the back to yellowish tan on the flanks, while the juveniles are pale olive. There are 3-4 parallel dusky, horizontal stripes that extend from the cheek along the body.

They can grow to a maximum total length of 21 cm (8.3 in), although 14 cm (5.6 in) is a more common total length.

The mud sunfish occurs along the eastern seaboard of the United States from southern New York south as far as northern Florida. The range of this species just extends into Alabama where they have been recorded in Beaver dam Creek in Washington County. There is a gap in their range in Maryland and Virginia, along the western part of Chesapeake Bay between the Susquehanna River and the Potomac River. It is not common anywhere in its range.

The mud sunfish is found in freshwaters which are stained dark with tannins. It has been recorded in slow-moving sluggish, well-vegetated creeks, rivers, ponds, lakes, and swamps. As its common name suggests it prefers substrates consisting of mud or detritus.