The Blackgut conger (Gnathophis bathytopos is an eel in the family Congridae (conger/garden eels). It was described by David G. Smith and Robert H. Kanazawa in 1977. It is a marine, deep water-dwelling eel which is known from the Straits of Florida, USA, and the southeastern Gulf of Mexico, in the western Atlantic Ocean. It dwells at a depth range of 180-370 metres. Males can reach a maximum total length of 35 centimetres.