Yes, a "wolf eel" - Congrogadus subducens. Despite its eel-like appearance, it's actually a member of the dottyback family (Pseudochromidae). It's the largest member of the Congrogadinae (eel blennies), but I don't think the smaller ones make it into the aquarium trade very often. The smaller species mostly feed on crustaceans, but C. subducens mainly feeds on fishes as an adult - juveniles mostly feed on crustaceans.
Tony