The dark-shouldered snake eel (Ophichthus cephalozona, also known commonly as the headsaddle snake eel, the black-neck snake eel, the blacksaddle snake eel, or the one-banded snake-eel[1]) is an eel in the family Ophichthidae (worm/snake eels).[2] It was described by Pieter Bleeker in 1864.[3] It is a tropical, marine eel which is known from the Pacific Ocean, including the East Indies, the Society Islands, the Mariana Islands, Queensland, the Marshall Islands, Micronesia, Japan, and India. It dwells at a depth range of 2–15 metres, and inhabits reefs. It forms burrows in mud and sand, and forages during the night. Males can reach a maximum total length of 115 centimetres.[2] The dark-shouldered snake eel is of no commercial interest to fisheries, but is sometimes caught in nets in the Ryukyu Islands.[2]