MolluscIreland - land and freshwater
  • Bithynia (Codiella) leachii (Sheppard 1823) Leach
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Bithynia (Codiella) leachii
© Dr Roy Anderson
Bithynia (Codiella) leachii
© Dr Roy Anderson

Map hosted by the National Biodiversity Data Centre, Waterford
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Like a small version of Bithynia tentaculata but the whorls are more convex and turreted and the sutures deeper. The aperture is a broad oval without a sharp point at the upper end. Found in calcareous streams and canals and occasionally in larger lakes. Possibly introduced in Ireland.

Key characteristics

  • Small, operculate shell forming a short cone
  • Sutures very deep and whorls convex
  • Spire shorter and less sharp than in Bithynia tentaculata
  • Aperture without a sharp point on the upper corner and operculum smoothly rounded


5-7 mm.

World Distribution

Found throughout Europe except the Arctic fringe, and into eastern Siberia. Distribution type: Eurasian Wide Temperate (65).

GBIF distribution map [open in new tab]

Irish Distribution

This was added to the Irish List by Welch (1908) from the Grand Canal in Cos. Kildare, Leix and Dublin and then from the River Barrow in Cos. Carlow and Kilkenny. Subsequently found in the Royal Canal as far west as Longford and south along the River Shannon to Limerick (Kerney, 1999). More recently it has been found in the large Shannon lakes (pers. comm. of G. A. Holyoak) and there is a record for Upper Lough Erne in Fermanagh (Anderson, in press). The construction of the Ballyconnell Canal between the Shannon System and the Erne System has apparently allowed this species to reach the Erne System as has happened already with Planorbarius corneus.


  • A species of slow-flowing water in rich lowland habitats such as canals and marshland drainage dykes in Britain
  • Found in similar places in Ireland but also within large lake systems
  • Prefers macrophyte-rich fringes in larger habitats


Least concern (lc).

Wikipedia link

Wikipedia page for Bithynia leachii

 Anderson, R., (2016). Bithynia (Codiella) leachii (Sheppard 1823). [In] MolluscIreland. Accessed on 2024-03-02.