Hexabranchus sanguineus (Ruppell & Leuckart, 1828)
spanish dancer
Hexabranchus sanguineus, spanish dancer

sub-classs Opisthobranchia > order Nudibranchia > sub-order Doridina > family Hexabranchidae

 

Top left - Spanish Dancer eggs in a characteristic bright pink rosette.
Top right - Juvenile Spanish Dancer
Bottom left - Adult Spanish Dancers are usually pure red, mottled, or occasionally yellow. As the name suggests, Hexabranchus sanguineus has six gills. There is no gill pouch into which the gills can retract.
Bottom right - Spanish dancers can swim freely. They feed on a variety of sponges.

Distribution =  Tropical Indo-west Pacific, Red Sea
Max size =   40cms, one of the largest nudibranchs

more info at Sea Slug Forum      more pics at nudipixel