Pseudosuccinea columella is a freshwater snail from the family Lymnaeidae and it is native to Americas. It is also well known species in Europe as a “hothouse alien”. It is inadvertently spreading in aquaria and in ponds within greenhouses. Unfortunately it has been found also in the wild in Europe.
The shell of Pseudosuccinea columella resembles a shell of a Succinea land snail. The height of the shell of this specimen is 10.5 mm.
It can float on the water.
As all other Lymnaeidae it has its eyes at the base of its non-retractile tentacles.
And as all other Lymnaeidae it is exchanging gas trough a breathing pore (pneumostome). Pseudosuccinea columella can slide up its tube like pneumostome like this:
Another sequence:
Ventral view with pneumostome extended:
References:
(in Polish) Jackiewicz M. 2000: Błotniarki Europy, Gastropoda, Pulmonata, Lymnaeidae.– Wydawnictwo Kontekst, Poznań 116 pp., pages 28-29. ISBN 83-911532-4-0.
Pointier J. P., Coustau C., Rondelaud D. & Theron A. 2007. Pseudosuccinea columella (Say 1817) (Gastropoda, Lymnaeidae), snail host of Fasciola hepatica: First record for France in the wild. – Parasitology Research 101(5): 1389–1392. doi:10.1007/s00436-007-0656-y
gastropods 
“Unfortunately it has been found also in the wild in Europe.”
Why ‘unfortunately’ ? Is this an invasive species ? Because other than that it looks darn cute 🙂
Hello, thank you for your comment. Yes, it is an invasive species with a high invasive potential according to the “2013 IUCN Red List of Threatened Species” record at http://www.iucnredlist.org/details/156043/0