Button Snail

The Button Snail (Modulus modulus) is a small snail that can grow to just under the diameter of a dime. These snails will consume diatoms, some species of cyanobacteria, fine textured hair algae and film algae on macroalgae, glass, and rocks in your aquarium. They have about a one year life span. When distressed they release a chemical that warns other Button Snails that there is danger in the area, usually a predatory snail. In response the snails change direction and move away from the distressed snail.

Caribbean species naturally expire in late Winter or early Spring. In the wild they spend their time cleaning seagrass, and will do a good job cleaning macroalgae in your saltwater planted tank, or the rocks and glass in your reef aquarium. They spend little time on the sand, and are as active in the day as they are at night. Modulus is the only genus in the family Modulidae. Despite their appearance and behavior, they are more closely related to Cerith snails than Trochus or Astraea Snails, and are in the Super Family Cerithioidea. 

This species is smallest when purchased in late Spring, and largest when purchased in early winter but near the end of their life. This species lays eggs that give birth to live young starting in February, and can reproduce in captivity. New young usually hatch on a rolling basis through May. Adults perish within a relatively short time after breeding. Button Snails can handle a lower salinity than most of the snails we carry, down to 1.015 long term without apparent consequence, as well as full salinity.