Fountain bladder snail
Physa fontinalis
The fountain bladder snail is a small, sinistral (left-handed) freshwater snail with a thin, glossy, and often translucent shell. It reaches a shell height of approximately 7 to 12 millimeters and is characterized by mantle fringes that extend over the shell. This species prefers clean, vegetation-rich, and oxygen-rich waters such as springs, streams, and clear lakes.
Details
Identification
Sinistral (left-handed) shell, mantle with finger-like lobes covering parts of the shell, thread-like tentacles, wide ovate aperture.
Social behavior
Solitary, does not exhibit distinct social behavior.
Diet
Feeds as a grazer on algal biofilms (periphyton), detritus, and soft plant tissues.
Hunting strategy
Grazing on surfaces using a radula (rasping tongue).
Spawning substrate
Smooth surfaces of aquatic plants, stones, or submerged wood.
Overwintering
Overwintering usually as adults or juveniles in the sediment or on deeper plant parts.
Ecology
Ecological role
Important consumer in aquatic food webs; converts primary production and detritus into animal biomass.
Natural predators
Fish, leeches, predatory insect larvae (e.g., dragonfly larvae), and waterfowl.
Competitor species
Other freshwater snails like Lymnaea stagnalis or invasive species like Physella acuta.
Ecosystem service
Supports water self-purification by consuming algae and organic decay products.
Threats
Water pollution, eutrophication, and loss of natural spring habitats.
Scientific profile
Profile
Distinguishing features
Sinistral (left-handed) shell that is very thin-walled, translucent, and highly glossy. The spire is short with a blunt apex. The aperture is wide and oval. The characteristic mantle digitations distinguish it from other families such as Lymnaeidae.
Diet
Algal periphyton, detritus, biofilms, and tender plant tissues.
Reproduction
Hermaphroditic; deposits gelatinous, kidney-shaped egg capsules on aquatic plants or hard substrates.
Role in food web
Primary consumer and decomposer; converts algal biomass and detritus into animal biomass.
Protection & threats
Main threats
Water pollution, eutrophication, loss of macrophyte beds, and competition from invasive species like Physella acuta.
Conservation measures
Protection and restoration of plant-rich lentic and lotic waters; reduction of nutrient inputs.