Hermissenda crassicornis is a species of small, brightly-colored, sea slug or nudibranch, a marine opisthobranch gastropod mollusk in the family Glaucidae.
This species does not really have a common name, but some people call it the "opalescent sea slug".
This nudibranch lives from Kodiak Island
, to Punta Eugenia
The species has also been observed in Bahia de los Angeles, Gulf of California, and in Japan.
It can be found in various habitats
, including the intertidal zone
of rocky shores but also in bays and estuaries
The species grows to be about 50 mm, or about 2 inches. The color of this nudibranch varies from place to place, but it is always easily recognizable by the orange stripe along the back.
This nudibranch feeds on hydroids
and other marine organisms such as ascidians
and sea anemones
. It sometimes attacks other nudibranchs, and will eat smaller specimens of its own species.
- Sea Slug Forum, species fact sheet:
- Behrens David W., 1980, ‘’Pacific Coast Nudibranchs: a guide to the opisthobranchs of the northeastern Pacific’’, Sea Challenger Books, California