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Faucet Snail (Bithynia tentaculata)

Faucet Snail

Photo credit: Michal Mana,

(Bithynia tentaculata)

Report this Species!

If you believe you have found this species anywhere in Pennsylvania, please report your findings to iMapInvasives by submitting an observation record.

Species at a Glance

The faucet snail is an aquatic snail native to Europe that threatens waterfowl, food webs, and can clog water intakes. It can quickly spread to inland waters, often reaching high densities and outcompeting native snails.


The shell is shiny, oval in shape, and ranges from light brown to black in color. The spire is relatively large and rounded, consisting of 5-6 somewhat flattened whorls. Adults can grow up to 12-15 mm (0.5 in) in length, but are generally smaller. A tough plate called the operculum tightly covers the shell opening (aperture). It is teardrop-shaped and displays concentric rings on adults. The aperture is on the right side when the shell is pointed up, and is less than half the height of the shell.

Similar Species

Native snails and young nonnative mystery snails can look similar to the faucet snail and can be difficult for non-experts to identify conclusively.


Commonly found in freshwater ponds, shallow lakes, and canals, the faucet snail attaches to objects in the water. It prefers gravel, sand, clay, mud, or the undersides of rocks as substrate in the fall and winter, and aquatic plants in warmer months. It can be found in depths of up to 5 m (16 ft).


This snail can spread by attaching to aquatic plants, waterfowl, boats, anchors, other recreational gear, and equipment placed in the water. It can also live in the water of livewells, bait buckets, and bilges. The faucet snail can live for up to one month in dry mud, so proper cleaning of equipment is essential before moving to a new water body.


Native to Europe, the faucet snail was introduced to the Great Lakes in the 1870s. It was most likely brought to North America unintentionally in the solid ballast of larger timber transport ships or in vegetation used in packing crates. In the Mid-Atlantic, this snail is established in New York, Pennsylvania, Maryland, Virginia, and Washington DC.


Note: Distribution data for this species may have changed since the publication of the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016), the source of information for this description.

Environmental Impacts

The faucet snail competes with native snails for food and resources and can clog water intake pipes and screens in municipal water systems. It is also an intermediate host for three intestinal trematode parasites that can kill waterfowl. These parasites do not pose a risk to humans consuming cooked fish or waterfowl.


Information for this species profile comes from the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016).

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