Freshwater Snail

Lymnaea stagnalis

The great pond snail (Lymnaea stagnalis) is one of the largest freshwater snails in Europe, with a distinctive elongated, right-handed spiral shell reaching up to 6 cm in length. The shell is thin, translucent, and light brown to yellowish, tapering to a pointed apex. The soft body is greyish to olive-green with small yellowish spots. This species inhabits still or slow-moving freshwater bodies including ponds, lakes, ditches, and calm river sections throughout Europe, northern Asia, and parts of North America where it has been introduced. It is a pulmonate snail, meaning it breathes air and must periodically visit the surface to replenish its air supply, creating a silvery bubble visible under its mantle. It feeds primarily on algae, decaying plant matter, and biofilm scraped from surfaces using its radula. As a hermaphrodite, each individual possesses both male and female reproductive organs and can either self-fertilize or mate reciprocally with another snail. Freshwater divers often spot them gliding along submerged logs, rocks, and aquatic plants.