Hexabranchidae is a taxonomic family of the colorful sea slugs which are known as nudibranchs.

Caloria is a genus of colorful sea slugs, aeolid nudibranchs.

Doridomorphidae is a taxonomic family of colorful sea slugs or nudibranchs.

These animals are colorful sea slugs, and they can superficially resemble nudibranchs, but are not very closely related to them.

Also, Elysia is a genus of colorful sea slugs.

Facelinidae is a taxonomic family of colorful sea slugs.

Bornella stellifer is a species of colorful sea slug, a nudibranch, a marine gastropod mollusk in the family Bornellidae.

The Spanish shawl, Flabellina iodinea, is a species of aeolid nudibranch, a very colorful sea slug.

Chelidonura is a genus of small, sometimes colorful, sea slugs.

Aglajidae is a family of often colorful, medium-sized, sea slugs, marine opisthobranch gastropod mollusks.