Cuthonella concinna is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Fionidae.

It has been reported from the Northeast Atlantic from Finmarken, Norway south to Normandy, France and in the NW Atlantic from New England as well as from the NE Pacific at Vancouver Island, Canada.

[3] In Britain and Ireland it is a northern species, occurring at Skomer Island, Pembrokeshire and in the Irish Sea and Scotland.

[3] Cuthonella concinna feeds on the hydroid Sertularia argentea, family Sertulariidae.

[4] Media related to Cuthonella concinna at Wikimedia Commons