This species is distinguished from its congeners by the following set of characters: poorly developed patterning of the body and fins; presence of black pigments in a vague midlateral stripe and 3-8 small saddles on the back, especially on caudal peduncle; presence of irregular markings on the body of some specimens, but not forming a clear pattern; absence of colour marks on most specimens, except for thin black lining along rays in the dorsal, anal and caudal fins, and, rarely, 1 or 2 faint blotches along lower edge of the caudal fin; absence of black patterning on pectoral and pelvic fins; conspicuous marking on body and paired fins (some large specimens may be almost completely dark brown) and the dorsal and caudal fins have several rows of conspicuous black dots; longitudinal groove on the snout between patches of large tubercles in males; absence of dorsal extensions or ridges along the dorsal side of the pectoral-fin rays; the pelvic fin not reaching the anal fin; and the anal fin not reaching the base of the caudal fin (Ref. 137931).