Cutthroat eels are a family, Synaphobranchidae, of eels, the only members of the suborder Synaphobranchoidei. They are found worldwide in temperate and tropical seas.[2][3]
Cutthroat eels range from 23 to 160 cm (9.1 to 63.0 in) in length. They are bottom-dwelling fish, found in deep waters down to about 3,700 m (12,100 ft).[4] They are distinguished by the presence of telescopic eyes in the larvae. In some classifications (for example, ITIS), this family is split, with Simenchelys in its own family, the Simenchelyidae.