Identification
To identify *Physella acuta*, look for the "left-handed" snail. Unlike most pond snails, this species is **sinistral**; if you hold the shell with the spire pointing up, the aperture (opening) is on the left side. The shell is thin, translucent, and a polished yellowish-horn color, usually reaching 10–17mm. Look closely through the shell to see the snail’s mantle, which is often beautifully mottled with dark, irregular spots. Its body is slender and grey-black, featuring two long, thread-like tentacles with eyes at the base.
Habitat & Range
Originally native to North America, *P. acuta* is now a cosmopolitan "globetrotter," found in freshwater ecosystems on every continent except Antarctica. It is incredibly hardy, thriving in ponds, slow-moving rivers, and drainage ditches. It is often the first species to colonize disturbed or polluted waters where oxygen is low, and it is a frequent "hitchhiker" in home aquariums.
Behaviour
These are the sprinters of the gastropod world. You’ll notice them gliding across surfaces with surprising speed. As **pulmonate** snails, they breathe air; you will often see them commute to the surface to refresh their "lung." They are prolific breeders, depositing clear, kidney-shaped gelatinous egg masses on the undersides of leaves or stones. When threatened, they exhibit a frantic "shaking" behavior, twisting their shells violently to dislodge predators like leeches.
Diet
*Physella acuta* is a vital cleanup crew member. Using a specialized, sandpaper-like tongue called a **radula**, it scrapes biofilm, algae, and decaying organic detritus from submerged surfaces. While they primarily target waste, they will occasionally graze on weakened aquatic plants or carrion.
Fascinating Fact
The Acute Bladder Snail can "walk" on the underside of the water’s surface! By utilizing surface tension, they create a mucous trail along the water-air interface, allowing them to glide upside down across the pond like they are walking on a glass ceiling.