Trimmatom pharus differs from T. nanus, T. offucius, and T. sagma in possessing scales on the body (vs naked) and branched pelvic fin rays (vs unbranched). Trimmatom zapotes, T. macropodus, and T. pharus all have body scales but T. zapotes has unbranched pelvic fin rays, and T. macropodus has the first four pelvic fin rays branched. Trimmatom pharus shares many meristic characteristics with T. eviotops including the presence of body scales and the branching of the first four pelvic fin rays; the two species do, however, differ in details of colour pattern. In preserved specimens the first body bar on T. eviotops crosses the pectoral base and the extends over the dorsum, passing backwards to the dorsal fin. In Trimmatom pharus the body bar which crosses the pectoral base crosses the dorsal surface anterior to the dorsal fin. Trimmatom eviotops has a broad dark saddle on the dorsall half of the caudal peduncle, while Trimmatom pharus has a narrow body bar or small dark saddle (Ref. 52310).