The mud sunfish prefers sluggish, weedy waters of 10–22 °C (50–72 °F), over muddy, detritus-strewn bottoms, and occurs in small lakes as well as riverine backwaters. The maximum recorded size of this species is 21 cm (8 in).
A. pomotis is currently the only species of genus Acantharchus Gill, 1864, but Baird had originally assigned it to Centrarchus. The generic name, Acantharchus, derives from the Greek άκανθα (thorn) and άρχος (ruler, in this sense "anus"). A. pomotis is sometimes also known as the mud bass.