Schismatogobius tuimanua is distinguished by the following characters: pectoral fin with 13-14 rays; pectoral fins banded with 4-5 rows of blackish bars; membrane in first dorsal fin posterior to spine 6 is not connected at base of spine in second dorsal fin; ventral surface of head and isthmus blackish, paler on chest and branchiostegals in female; and pelvic disc banded with usually two or three rows of black spots (Ref. 116768).