A nudibranch /ˈnjuːdɨbræŋk/ is a member of what is now a taxonomic clade, and what was previously a suborder, of soft-bodied, marine gastropod mollusks which shed their shell after their larval stage. They are noted for their often extraordinary colors and striking forms. The clade Nudibranchia is the largest clade within the heterobranchs, with more than 3,000 described species.
The word "nudibranch" comes from the Latin nudus, naked, and the Greek βραγχια, brankhia, gills.
Nudibranchs are often casually called "sea slugs", but many sea slugs belong to several taxonomic groups which are not closely related to nudibranchs. A number of these other sea slugs (such as the colorful Aglajidae) are often confused with nudibranchs.

  • Nudibranch
  • Hermissenda crassicornis
  • Hilton's Aeolid
  • Monterey sea-lemon
  • Olive's aeolid
  • San Diego Droid
  • Santa Barbara Janolus
  • Spanish Shawl
  • The Mimic
  • White Dendronotid
  • White Dendronotid
  • Nudibranch