The Spanish dancer, scientific name Hexabranchus sanguineus (literally meaning "blood-colored six-gills"), is a dorid nudibranch, a very large and colorful sea slug, a marine gastropod mollusk in the family Hexabranchidae.
Description
Hexabranchus sanguineus is a large dorid nudibranch which commonly grows up to a maximum length of 25 cm, with some reports to 40 cm in the Red Sea. The latter is coveted by some other species of nudibranch as Favorinus tsuruganus or Favorinus japonicus.
The emperor shrimp, Periclimenes imperator, is a commensal shrimp that is commonly found living on Hexabranchus sanguineus.