Histiobranchus australis, the southern cutthroat eel, is a cutthroat eel in the family Synaphobranchidae. It dwells at a depth range of 950 to 3,001 metres (3,117 to 9,846 ft) as it leads a benthic lifestyle. It is a marine, deep water-dwelling eel which is known from the southern Atlantic, Indian, and Pacific Ocean. It is also known as the angel eel, spider eel, cutthroat fish, or the southern cutthroat. Synonyms for it are Synaphobranchus australis.