Astrea Snail

The Astrea snail (Astraea tecta) is a popular marine gastropod mollusk native to the warm waters of the Caribbean and Atlantic Ocean. Easily recognized by its thick, conical shell that resembles a star or pyramid, this hardy herbivore typically reaches a maximum size of 1 to 2 inches (2.5 to 5 centimeters) in diameter. These snails are staple members of saltwater "clean-up crews" because of their voracious appetite for nuisance film algae, hair algae, and diatoms. They spend their time relentlessly scraping algae off live rock, aquarium glass, and pump equipment using their rough radula (tongue), helping maintain clean glass and rockwork without harming corals or other invertebrates.

In a home aquarium, Astrea snails require stable calcium and magnesium levels to maintain their dense shells, along with sufficient algae growth to prevent starvation. Their primary vulnerability is their shape: if an Astrea snail falls onto its back on fine sand, its heavy, top-heavy shell makes it difficult to flip itself right-side up, requiring human intervention to flip them over before crabs or predatory fish take advantage.