Stout-bodied, nearly cylindrical fish. Dorsal fin extends more than half the length of the back and has more than 45 rays. Tail fin rounded, with hind part of backbone curving into upper part of fin. Head lacks scales. Each nostril has a barbel-like flap. Fins lack spines. Upperparts mottled olive-green, shading to pale green on belly. Dorsal and tail fins dark green with darker bands or bars. Young have a black spot near the upper part of the tail base. This spot can persist in adults.