Strongly resembling the rock bass in general color and shape, the mud sunﬁsh is not actually a member of the Lepomis sunﬁsh genus, although it is called a sunﬁsh. It has a rectangular, compressed body that is dusky reddish brown on the back and pale brownish underneath.
The lateral-line scales are pale, and along the arch of the lateral line is a broad irregular stripe of dark scales about three scale rows wide. Below the lateral line are two straight dark bands, each two scale rows wide, and an incomplete third, lower stripe one scale wide. It is distinguished from the similar rock bass by the shape of the tail, which is round in the mud sunﬁsh and forked in the rock bass.
Also, young mud sunﬁsh have wavy dark lines along the sides, whereas young rock bass have a checkerboard pattern of squarish blotches. The mud sunﬁsh may reach a maximum of 61⁄2 inches. In North America, mud sunﬁsh are widely distributed in the Atlantic Coastal Plain and the lower Piedmont drainages from the Hudson River in New York to the St. Johns River in Florida, and in Gulf Coastal Plain drainages of northern Florida and southern Georgia from the Suwanee River to the St. Marks River.
They usually occur over mud or silt in vegetated lakes, pools, and backwaters of creeks and in small to medium rivers. Adult ﬁsh are frequently seen resting head down in vegetation.
This species is generally an incidental catch for anglers.