Polypera is a monotypic genus of marine ray-finned fish belonging to the family Liparidae, the snailfishes. Its only species is Polypera simushirae which is found in the northwestern Pacific Ocean at depths down to . This species grows to a length of TL and has been recorded at a maximum weight of . This species is the only known member of its genus. It is probably the largest of the snailfishes.