The Astrea Snail is easily recognizable by its unique triangular-shaped shell that makes it stand out from other sea snails. Astrea snails are a popular choice for a Reef Tank Clean Up Crew because they are busy workers, happily eating algae off live rock and aquarium glass. The Astraea Snail has an appetite for algae, especially the kinds that can be troublesome in saltwater aquariums, like hair algae, cyanobacteria, and diatoms. If it accidentally flips over, it might have trouble getting back up and need assistance when flipped.