The fish has a small, inferior mouth. The scales on the head and body are ctenoid (rough). The gill rakers are short and club-shaped, numbering 9–11 on the lower limb of the first gill arch. The caudal fin is rhomboidal. The body is dark, but pigments are sometimes irregular and concentrated into short, dark bars dorsally or on the spinous dorsal fin. Other fins are often black, and a dark blotch is visible through the gill cover.