Peringia is a genus of very small snails with gills and an operculum, gastropod mollusks in the family Hydrobiidae. This genus has become a synonym for Hydrobia Hartmann, 1821.These snails live in intermediate habitats at high tide level, on mud, in protected estuarine and coastal areas. Because of this habitat these snails are sometimes categorized as marine, sometimes as aquatic in general, and sometimes are included in lists of land snails.