The dark deepwater snake-eel (Ophichthus aphotistos) is an eel in the family Ophichthidae. It was described by John E. McCosker and Chen Yu-Yun in 2000. It is a marine, deep water-dwelling eel which is known from Taiwan, in the northwestern Pacific Ocean. It dwells at a depth range of 36-1350 m (most commonly 250-350 m), and inhabits sand and mud. Specimens have been observed in burrows with only their heads exposed, or resting on sediment with their bodies curved in an S shape. Females can reach a maximum total length of 62.8 cm.