Gymnocranius griseus

Gymnocranius grandoculis differs in having horizontal, wavy blue lines present for specimens >20 cm TL on snout and cheek (vs. no blue markings) and dark bars along body, 4^th bar running from 6^th dorsal-fin spine to mid pelvic-anal space (vs. dark bars along body, 4^th bar running from 6^th dorsal-fin spine to anal-fin origin <20 cm SL).

Gymnocranius elongatus differs in having a deeply forked caudal fin, the median rays shorter than eye diameter (vs. moderately forked, the median rays slightly longer than eye diameter) and lower edge of eye level with snout tip to middle of caudal-fin fork (vs. lower edge of eye slightly above line from snout tip to middle of caudal-fin fork).

Gymnocranius frenatus differs in having 3 or 4 oblique blue lines on snout and cheek (vs. no markings).

Gymnocranius euanus differs in having 4½ scale rows between lateral line and base of middle dorsal-fin spines (vs. 5½).

Gymnocranius satoi differs in having blue speckles on snout and cheek (vs. blue markings absent) and inner edge of caudal-fin lobes straight (vs. convex).

Gymnocranius obesus differs in having a dark bar running from below sixth dorsal-fin spine to anal-fin origin (vs. dark bar running from below sixth dorsal-fin spine to mid pelvic-anal space) and 4–6 front scales on the top of head (vs. 9–11).