Photo of the day (90): Lymnaea stagnalis

Lymnaea stagnalis is a species of a common holarctic freshwater snail from the family Lymnaeidae. It usually inhabits standing waters and also temporary pools. What will happen to Lymnaea stagnalis snails when is the temporary pool out of water?

This is a temporary pool in the southern part of the Litovelské Pomoraví Protected Landscape Area, Czech Republic at June 29, 2018.Lymnaea stagnalisFortunately Lymnaea stagnalis can survive outside water for some time. Most of them were still alive.

Lymnaea stagnalisThere are also some Stagnicola turricula snails (those smaller ones) among Lymnaea stagnalis. It is also species from the family Lymnaeidae.Lymnaea stagnalis and Stagnicola turriculaReferences


How to remove Chaetogaster limnaei limnaei

Chaetogaster limnaei limnaei is a species of a small freshwater oligochaete that is an episymbiont on freshwater snails. It is considered to be ubiquitous.

I have collected one Lymnaea stagnalis and few Stagnicola sp. species in the outdoor shop of various plants including wetland plants and freshwater plants. I noticed tiny white worms on snails later when I put snails into my aquaria.

These worms are predators of various aquatic animals including medically important trematodes. Trematodes parazitises snails as well as humans. These Chaetogaster worms eat larvae (miracidia and cercariae) of trematodes and they are helping to snails in this way. The more Chaetogaster worms are on the snail, the the more intense trematode infection is.

I do not know how many trematodes were in snails or in the environment, but maybe lot of them.

Chaetogaster limnaei limnaei on Stagnicola sp.

Chaetogaster limnaei limnaei on Stagnicola spFrom time to time, I used to watch them and I was waiting for the time when they would multiply and when they will torture snail to death. It did not happen.

One day (do not know it exactly, probably few months later) I noticed that all worms disappeared. I did not know why they were gone.

Later I found the reason in the 1974 thesis. Chaetogaster limnaei limnaei is highly sensitive to temperatures above 24 °C. Such a temperature reduces or completely eliminates these worms. Therefore, If you transport worms from their natural environment to your tropical aquarium, there is no need to worry. If you have aquaria with aquarium heater, they are bound to be killed by high temperature. Worms are killed in summer heat as well.

All other photos show Chaetogaster limnaei limnaei on the same Lymnaea stagnalis specimen.

There does not seem to be anything strange from the general point of view. Nevertheless, there are still many worms on the snail’s body.

Lymnaea stagnalisChaetogaster limnaei limnei on Lymnaea stagnalisThey are in mantle cavity too.

Chaetogaster limnaei limnei on Lymnaea stagnalisDetail of one Chaetogaster limnaei limnaei on the left tentacle of Lymnaea stagnalis.

Chaetogaster limnaei limneiFew Chaetogaster limnaei limnaei on the left tentacle of Lymnaea stagnalis.

Chaetogaster limnaei limneiOne Chaetogaster limnaei limnaei.

Chaetogaster limnaei limneiReferences

Hopkins S. R., Wyderko J. A., Sheehy R. R., Belden L. K., Wojdak J. M. 2013: “Parasite predators exhibit a rapid numerical response to increased parasite abundance and reduce transmission to hosts“. Ecology and Evolution 2013; 3(13): 4427–4438.

Sankurathri C. S. 1974: “Effects of thermal effluent on the population dynamics of Physa gyrina Say (Mollusca: Gastropoda) and its helminth parasites at Wabamun Lake, Alberta“. Thesis, Department of Zoology, The University of Alberta, Edmonton, Alberta, 132 pp.

Photo of the day (21): Radix auricularia

Radix auricularia is a freshwater snail from the family Lymnaeidae. This species is native to Eurasia.

The shell of an adult snail has an ear shaped aperture, but I have taken photos af a juvenile snail.  The height of the shell of this juvenile snail is 14 mm. All of these photos shows the same specimen.

Right lateral view of a crawling snail:


Two frontal views:


Coloration of the mantle:


This apertural view of a live snail outside water shows the opened pneumostome:


When the pneumostome is closed, the inflated respiratory cavity is clearly visible on this photo on the right side of the body:


Apertural view of a snail in the aquarium shows also its foot and opened mouth. It is scraping algae from the glass:


Photo of the day (18): Pseudosuccinea columella

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:



(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