Mud Bithynia

The height of shell is usually no larger than 12–15 mm. The snail is sexually mature by the time the height of shell reaches 8 mm in size.

The faucet snail has a shiny pale brown shell, oval in shape, with a relatively large and rounded spire consisting of 5–6 somewhat flattened whorls, no umbilicus, and a very thick lip. The aperture is less than half the height of the shell.

Adult Bithynia tentaculata possess a white, calcareous, tear-drop to oval-shaped operculum with distinct concentric rings. The operculum of juveniles, however, is spirally marked. The operculum (on the back of the foot) is always situated very close to the aperture of the shell. The animal itself has pointed, long tentacles and a simple foot with the right cervical lobe acting as a channel for water.

The distribution of Bithynia tentaculata is Palearctic. The species occurs in:

Germany – common species overall in Germany, but is listed as endangered (gefährdet) in Saxony and in Thuringia

Bulgaria – There is southern distribution border of Bithynia tentaculata in northern Bulgaria.

Bithynia tentaculata has been mentioned from Greece, but it does not occur there. It probably does not occur in Turkey and in Iran.

This species functions as both a scraper and a collector-filterer, grazing on algae on the substrate, as well as using its gills to filter suspended algae from the water column. When filter feeding, algae is sucked in, condensed, and then passed out between the right tentacle and exhalant siphon in pellet-like packages which are then eaten. The ability to filter feed may play a role in allowing populations of the faucet snail to survive at high densities in relatively eutrophic, anthropogenically influenced water bodies. Bithynia tentaculata feeds selectively on food items. The faucet snail is known in Eurasia to feed on black fly larvae.

This snail lives in slow-running freshwater habitat such as low-velocity rivers, and standing-water bodies such as lakes. The species flourishes in calcium-rich waters.

It is commonly found in freshwater ponds, shallow lakes, and canals. This species is found on the substrate in fall and winter (including gravel, sand, clay, mud or undersides of rocks) and on aquatic macrophytes (including milfoil, Myriophyllum spicatum and muskgrass, Chara spp.) in warmer months.

Bithynia tentaculata is dioecious (it has two separate sexes) and lays its eggs on rocks, wood and shells in organized aggregates arranged in double rows, in clumps of 1 to 77. Egg-laying occurs from May to July when water temperature is 20 °C (68 °F) or higher, and sometimes a second time in October and November by females born early in the year. The density of eggs on the substrate can sometimes reach 155 clumps/m2 (14.4 clumps/sq ft). Fecundity may reach up to 347 eggs and is greatest for the 2nd year class. Eggs hatch in three weeks to three months, depending on water temperature. Oocytes develop poorly at temperatures of 30 to 34 °C (86 to 93 °F). Growth usually does not occur from September to May. The lifespan varies regionally and can be anywhere from 17 to 39 months.