Acute Bladder Snail

P. acuta is widely dispersed across the globe, largely due to the aquarium trade. It is an invasive species which can be found on all continents except Antarctica and is considered by Dillon and colleagues (2002) as "the world's most cosmopolitan freshwater gastropod". P. acuta was originally thought to be a European species, as its first record in North America following Draparnaud's initial description was only published in 1997. However, reproductive isolation experiments and molecular genetic studies revealed it to be the same species as the North American Physella heterostropha and Physa integra. Comparative anatomy, fossil evidence, and phylogenetic data also support a North American origin, specifically within the United States. However, its exact native range within the country remains debated, with hypotheses for both eastern and western origins. The timing and pathway of P. acuta's first arrival in Europe are also uncertain. Anderson (2003) links it back to eastern U.S. populations via the 18th-century cotton trade. This hypothesis is based on the fact that Draparnaud's description happened during a time when the U.S. and France had trade relations, with traffic between the ports of Mississippi and Bordeaux. Other hypotheses for P. acuta's first introduction to Europe have also been proposed, including natural dispersal by birds. Once within Europe, P. …

P. acuta can occupy a variety of freshwater habitats as well as habitats varying widely in water availability. As a pulmonate snail, it tolerates harsh environmental conditions such as polluted and eutrophic (oxygen-deprived) waters, since it is able to come to the surface to breathe air. P. acuta has been reported in lakes, ponds, streams, and ditches, as well as artificial sites such as reservoirs, sewage drains, and irrigation systems. It is a scraper feeder and uses its radula (a tongue-like structure covered in small chitinous teeth) to scrape green algae, diatoms, and aquatic plants from the surface. P. acuta is a simultaneous hermaphrodite which is self-compatible, meaning it is capable of both outcrossing (reproduction with another individual) and self-fertilisation. In natural populations, reproduction occurs mainly by outcrossing, but self-fertilisation rates still remain between 10 and 30 percent and can increase as an adaptation strategy when mates are scarce. During P. acuta's reproductive development, snails first reach outcrossing maturity after about 5–7 weeks, while self-fertilisation maturity comes at around 14 weeks. Sexually mature adults breed year-round and lay 50–100 eggs per week. Eggs are deposited in elongate gelatinous sacs, which they attach to rock, compacted mud, or the shells of other P. acuta. Eggs hatch after 15–20 days. …

Physella acuta is commonly known as European physa, tadpole snail, sewage snail, bladder snail, or acute bladder snail. The species was first described as Physa acuta in 1805 by Jacques Philippe Raymond Draparnaud, based on a specimen found in the Garonne catchment in France. The specific epithet acuta is Latin for 'sharp'. In 1817 Thomas Say independently described the same species in Pennsylvania, naming it Physa heterostropha. This and several other newly described species, such as Physella virgata and Physella integra (described from North America), as well as Physella cubensis (described from Central America), were considered distinct from each other until molecular and reproductive studies at the beginning of the 21st century revealed them to be synonyms of P. acuta. Since 2021, molecular phylogenetic studies (which investigate evolutionary relationships using genetic data) have reported stronger evidence for moving the species from its original genus Physa to Physella.

As of 2025 the World Register of Marine Species (WoRMS) accepts the taxonomic classification proposed by Albrecht and colleagues (2025). The authors place P. acuta in the genus Physella, with Physa (the genus to which it was previously assigned) and Stenophysa as sister groups. Together, these three genera form the subfamily named Physinae. The family Physidae consists of Physinae and the genus Aplexa. P. …