Bithynia leachii is a widespread freshwater snail in Europe and it is a least concern species. This snail can live in natural and unpolluted wetlands only. In some areas, for example in the Czech Republic, it is critically endangered, because it inhabits a very limited area there.
There is seen on this frontal view, that the shell has very convex whorls and a very deep suture. This feature distinguish it from other Bithynia species.
Right side view of the same snail:
Beran L. & Horsák M. (2009) “Distribution of Bithynia leachii (Sheppard, 1823) and Bithynia troschelii (Paasch, 1842) (Gastropoda: Bithyniidae) in the Czech Republic“. Malacologica Bohemoslovaca 8: 19-23.
Vavrová L., Cianfanelli S., Prie V., Georgiev D. & Ghamizi M. (2010). “Bithynia leachii“. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 18 January 2015.