About Tridentiger trigonocephalus (Gill, 1859)
Tridentiger trigonocephalus, commonly known as the chameleon goby, reaches a maximum total length of 11 centimetres (4.3 inches). Its base body color is pale greyish-brown, with a white-speckled head and two longitudinal black bands that run along the flank from the head to the caudal peduncle. Both of its dorsal fins may have white speckles and a brown longitudinal stripe, and the anal fin has an orange or grey band running across its centre. In certain conditions, this fish can darken its overall color to the point that the black bands become nearly invisible. This species is very similar in appearance to the Shimofuri goby (Tridentiger bifasciatus), but differs in several key traits: the chameleon goby has no white spots on the underside of its head, and has a white margin along its second dorsal fin and anal fins. In contrast, T. bifasciatus has white spots on both the upper and lower sections of the head, and an orange-red margin on the second dorsal and anal fins, while lacking the distinctive stripes that T. trigonocephalus has on these fins. The two species also differ in preferred habitat salinity: T. bifasciatus prefers waters with a salinity lower than 22 parts per thousand, while T. trigonocephalus prefers higher salinity environments. The chameleon goby is native to the eastern coast of Asia, with a native range that includes Japan, Korea, China, and Siberia. There have been confirmed reports of this species found in the Black Sea, and it was recently recorded in the eastern Mediterranean Sea at Ashdod harbour, Israel. It is a demersal fish that lives and feeds near the seabed, and can be found in bays and rocky coasts, as well as in brackish water and freshwater lakes. It typically hides in crevices, under stones, inside burrows, or among seagrasses.
