The striped goby was characterized by having more than 50 scales in a longitudinal row and 2 black longitudinal bands from the head to the tail. It has been regarded as 1 species since Tomiyarna (1936) grouped several nominal species into one, Tridentiger trigonocephalus (Gill, 1858). But detailed study has revealed that it can be classified into 2 separate species, T. trigonocephalus and Tridentiger bifasciatus Steindachner, 1881, on the basis of the difference mainly in the forms of the sensory canals and pectoral fins and in the coloration. T. trigonocephalus has been collected from Hokkaido to Kyushu in Japan, and in Korea, China, and Hong Kong abroad. It has immigrated into both California, U.S.A., and New South Wales and Victoria, Australia. T. bifasciatus has been collected in the same area as T. trigonocephalus in Japan, and in the Soviet Union, Korea, China, and Taiwan abroad. Both species inhabit brackish and sea water with stony bottoms, and are often found in the same place. However, T. trigonocephalus has seldom been found in very dilute brackish water, and T. bifasciatus has not been found in undiluted sea water. The type specimen of T. trigonocephalus has not been found, but the identification to T. trigonocephalus was decided on the basis of the closeness of the numbers of the 2nd dorsal and anal fin rays to those of the original description, which were 14 and 13, respectively. In addition, the type specimen was collected in the port of Hong Kong, where the water is not diluted and is unlikely to be suitable as habitat for T. bifasciatus.