The Threadfin scat (Rhinoprenes pentanemus) is a species of ephippid native to the Pacific Ocean around Papua New Guinea and Australia.

This fish eats algae and also sewage.

[citation needed] This species grows to a length of 15 centimetres (5.9 in) TL.

This species is the only known member of the genus Rhinoprenes.

This Acanthuriformes-related article is a stub.