Polypera is a monospecific genus of marine ray-finned fish belonging to the family Liparidae, the snailfishes. It only species is Polypera simushirae which is found in the northwestern Pacific Ocean where it is found at depths down to 833m (2,733feet). This species grows to a length of 77cm (30inches) TL and has been recorded at a maximum weight of 11kg (24lb). This species is the only known member of its genus. It is probably, the largest of the snailfishes.