3 Large (1/2"+) Golden Mystery Snails (Live Snails) - Eats Algae and Detritus, Safe for FW Fish, Shrimp, and Live Plants All livestock sold by CAS are 100% guaranteed to arrive alive and stay that way for 3 days after receiving date. The largest and most popular snail for freshwater aquariums. A dynamic and interesting addition to any tank. Mystery snails eat most unwanted items in aquariums such as algae, left over fish food, bacteria scum, fungus, and more! They will not harm live plants or other inhabitants in your tank. Don't get a random type of snail from the competition! Mystery snails sold by CAS are all of the Pomacea Diffusa species. Only we guarantee our mystery snails to be of a single species.