The Purple Nudibranch is colored in shades of purple, white, and yellow.Nudibranch are part of a Class of Mollusks known as Gastropods. These snail-like creatures do not use a shell for protection. Most Nudibranch have an elongated oval shaped body with a mantle and external gills. The external gills are appendages that extend out towards the rear of their body. Nudibranch are usually carnivores and use rhinophores for sensing food as well as oral tentacles.