Lettuce Sea Slug GALLERYTridachia crispata
The skin ruffles on a Nudibranch's body help the animal absorb oxygen and are are considered external gills. If you are very observant, you'll see these sea slugs in areas of algae,(which they feed on) both on reefs and sandy bottoms and coral rubble. They have two fairly large rhinophores (antennae) on the head. The most common color is green with white body spots and green and white ruffles, but the ruffles can also be shades of red and blue. They can grow to about 2 inches in length.