This species is distinguished by the following characters: scales on cheeks and opercle; scales in predorsal midline 8-9; unbranched pectoral fin rays 16; branched 5th pelvic fin ray, 45-50% length of 4th ray; total gill rakers 20-22; broad interorbital (46-63% pupil width) with narrow crease-like postorbital trench ending at posterior-most papilla in row p; small nasal apparatus placed on the anterior one-third of snout with posterior nares forming posterodorsa margin of nasal sac; papillae in row p 7 (with a single papilla below row n); when alive or freshly collected, the dorsal surface of eye is dark blue; when preserved, with fairly evenly distributed melanophores over dorsal surface of snout (Ref. 118315).

Differs from Trimma meityae by having 16 pectoral fin rays (vs. 17-18), a branched 5th pelvic fin ray (vs. unbranched), with 7 papillae in row 'p' (vs. 8 papillae); and in live specimens, the blue colour over the top of the eyes is much darker in this species than in T. meityae (Ref. 118315).