Ilyophis nigeli is an eel in the family Synaphobranchidae (cutthroat eels).[1] It was described by Yuri Nikolaevich Shcherbachev and Kenneth J. Sulak in 1997.[2] It is a marine, deep water-dwelling eel which is known from Japan, in the northwestern Pacific Ocean. It is known to dwell at a depth range of 700to. Males can reach a maximum total length of 51.3cm (20.2inches).[1]
The species epithet "nigeli" was given in honour of Nigel R. Merrett, credited with making "substantial contributions" to the knowledge of the synaphobranchid eels.[1]