MolluscIreland - land and freshwater
  • Bithynia (Bithynia) tentaculata (Linnaeus 1758) Common Bithynia
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Bithynia (Bithynia) tentaculata
© Dr Roy Anderson
Bithynia (Bithynia) tentaculata
© Dr Roy Anderson
Bithynia (Bithynia) tentaculata
© Dr Roy Anderson

Map hosted by the National Biodiversity Data Centre, Waterford
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A slightly globose, short-conical operculate shell with deep sutures and large body whorl found commonly in a variety of freshwaters.

Key characteristics

  • Medium-sized operculate shell with large body whorl forming a short cone shape
  • Sutures deep
  • Aperture a broad oval coming to a point at its upper end, easily seen in the shape of the operculum


8-13 mm.

World Distribution

Found across Europe from the Mediterranean to the Arctic fringes and east to eastern Siberia. Distribution type: Eureosiberian Wide Temperate (64).

GBIF distribution map [open in new tab]

Irish Distribution

Widespread and generally common in the central plain of Ireland but decreasing strongly towards the north-west and south-west.


  • Very tolerant of enrichment and often found in eutrophic lakes and rivers
  • Prefers macrophyte-rich waters with a muddy bottom
  • Tolerant of soft water in larger water bodies but not found in acidic (peaty) habitats

Red List status

  • Least concern (lc).

Wikipedia link

Wikipedia page for Bithynia tentaculata

 Anderson, R., (2016). Bithynia (Bithynia) tentaculata (Linnaeus 1758). [In] MolluscIreland. Accessed on 2024-03-02.