This species is distinguished by the following characters: body moderately deep and compressed, its depth 2.1-2.5 times in standard length or SL (smaller individuals are deeper-bodied); snout relatively short, 6-6.9 times in SL; eye 3.2-4.5 times in head length (at 12-28 cm SL); mouth small; teeth spatulate, close-set, with denticulate edges, and small for the genus; total gill rakers on first gill arch 13-15; continuous, unnotched dorsal fin IX,24-26; A III,23-24; caudal fin emarginate to lunate, concavity 6.5-9 times in SL (concavity is greater in larger individuals); caudal peduncle narrow, the least depth 10-12 times in SL with a lancet-like spine on each side which folds into a deep horizontal groove; stomach large, U-shaped, thin-walled with large, thorn-like papillae on inner surface; colour brown with longitudinal blue lines on head and body; a yellow area behind eye and 2 yellow bands extending anteriorly from eye; when alive, this fish is capable of changing its ground colour from dark brown to pale blue (Ref. 9808).