Japanese Moray Eel

Gymnothorax kidako

The Japanese moray eel (Gymnothorax kidako) is a large moray reaching up to 90 cm in length, found primarily in the temperate and subtropical waters of the northwestern Pacific. It has a robust, muscular body with mottled brown to dark brownish-grey coloration marked with irregular lighter spots and patches. Like all morays, it lacks pectoral and pelvic fins and has a continuous dorsal fin running along its back. It constantly opens and closes its mouth to pump water over its gills, a behavior that can appear threatening but is simply respiration. This species inhabits rocky reefs, boulder fields, and crevice-rich environments where it shelters during the day and hunts at night. It feeds on fish, octopus, and crustaceans, using its keen sense of smell to locate prey in the dark. Divers commonly encounter it peering from holes and overhangs on Japanese reef sites, often accompanied by cleaner shrimp that pick parasites from its skin and mouth. It is generally not aggressive toward divers unless provoked or fed.