Facciolella castlei is an eel in the family Nettastomatidae (duckbill/witch eels).[1] It was described by Nikolai Vasilyevich Parin and Emma Stanislavovna Karmovskaya in 1985.[2] It is a marine, deep water-dwelling eel which is known from Chile, in the southeastern Pacific Ocean. The type specimen was retrieved from a depth of 230 metres.[1]