The smallmouth spiny eel (Polyacanthonotus rissoanus), also called the shortspine tapirfish, is a species of deep-sea spiny eel.
The smallmouth spiny eel is silver or brown in colour, with a maximum length of . It has 26âÂÂ36 dorsal soft rays. It looks similar to Polyacanthonotus africanus but its lateral line is lighter and less distinct. It has a small mouth and a short preoral snout. Mature males are distinguished by their black nostrils.
The smallmouth spiny eel lives in the Arctic waters off of Canada and in the North Atlantic Ocean off of Iceland, Ireland and Great Britain; it has also been observed in the waters off South Africa and in the Tasman Sea. It is a benthic and bathydemersal species, living at depths of .
Polyacanthonotus rissoanus feeds on coelenterates, worms and crustaceans.