Sea Slugs are a type of invertebrate that are actually often evolved from snails that lost their shells. These include mostly nudibranchs. They are often brilliantly colorful and seem to glide around the aquarium. They will be welcomed additions to cleaner crews and colorful additions to most reef tanks.
Possible inclusions are: Lettuce Nudibranch, Berghia Nudibranch, Purple Sea Slug, Orange Dragon Slug, Spanish Dancer Nudibranch, or Blue Velvet Nudibranch.