Catriona aurantia is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Trinchesiidae.

[1] It was incorrectly synonymised with Catriona gymnota from the Western Atlantic but shown to be a distinct species by DNA analysis.

[3] This species has a translucent white body and slightly swollen cerata.

Individuals are thought to feed by eating through the stems of the hydroid rather than on the polyps.

Usually found in exposed places, in strong tidal streams, and in shallow water, from 0 m to 20 m depth.