Freshwater snail

Freshwater snails are gastropod mollusks that live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs to major rivers. The great majority of freshwater gastropods have a shell, with very few exceptions. Some groups of snails that live in freshwater respire using gills, whereas other groups need to reach the surface to breathe air. In addition, some are amphibious and have both gills and a lung (e.g. Ampullariidae). Most feed on algae, but many are detritivores and some are filter feeders.

Freshwater snails are indirectly among the deadliest animals to humans, as they carry parasitic worms that cause schistosomiasis, a disease estimated to kill between 10,000 and 200,000 people annually.^[1][2]

There are thousands of known species, and at least 33–38 independent lineages of gastropods have successfully colonized freshwater environments.^[3] It is not possible to quantify the exact number of these lineages yet, because they have yet to be clarified within the Cerithioidea.^[3] From six to eight of these independent lineages occur in North America.^[4]