Lepomis, the generic name, is Greek and means "scaled gill cover." The species epithet microlophus is Greek for "small nape." The redear is a deep-bodied sunfish with a relatively small mouth. Color ranges from dark olive green above to almost white on the belly. The sides are usually yellow to green. The spinous dorsal fin, which is anterior to the soft dorsal fin, is normally equipped with 10 spines, although 9 or 11 spines are sometimes observed, and it is broadly connected to the soft dorsal fin. The anal fin has three spines. The species' most distinct characteristic is the red edge on the opercle ("ear") flap of the male (orange on the female). The opercle flap is never greatly elongated as it is in species such as the redbreast sunfish (Lepomis auritus) or the longear sunfish (L. megalotis).