Aquatic Arts 3 Black Mystery Snails (Algae Eaters) (young adult 1/2 to 2+ inch) All Aquatic ArtsTM (formerly InvertObsessionTM) brand plants and animals come with a 100% live arrival guarantee, plus free email support directly from the owners! One of the largest plant-safe freshwater snails, Mystery Snails are a popular and attractive addition to any aquarium. Can grow to over 2 inches - one of the largest freshwater snails in the aquarium hobby. Feeds on leftover food or almost any kind of fish food. Effective at algae control, and they also eat uneaten fish food. Mystery Snails move around much faster and are more active than other snails!