Lymnaea stagnalis, better known as the Great Pond Snail, is a species of large air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Lymnaeidae. Lymnaea stagnalis (Great Pond Snail) occurs throughout Europe, northern Asia and North America, a distribution which is likely to have been affected by the introduction of this species to garden ponds. Lymnaea stagnalis is the largest pond snail in Britain. The snails are found in still or slow-moving waters where there is plenty of aquatic vegetation. As the specific part of the Latin name, stagnalis, suggests, this species prefers stagnant water. Lymnaea stagnalis is classified as Least Concern (LC) on the IUCN Red List. It is common and widespread in England, but is scarce in Scotland and Wales. We supply snails originally collected and bred in Scotland.
The height of an adult shell of this species ranges from 45 – 60 mm. The width of an adult shell ranges from 20 – 30 mm. The 40 – 50 x 22 – 30 mm (median) shell has 4.5 – 6 weakly convex whorls. The upper whorls are pointed, the last whorl is suddenly inflated, so that its diameter is more than a continuous increase of that of the upper whorls. The umbilicus is closed. The Great Pond Snail has a shiny yellowish brown shell, with a tall, slender and pointed spire. The shell walls are delicate and fairly transparent; they have fine markings, more prominent growth lines and variable dents on the surface.
Using its rasping tongue, known as a radula, Lymnaea stagnalis feeds on both plant and animal matter, leaving behind distinctive feeding marks. It can even attack newts, small fishes, and water beetle larvae and may occasionally be cannibalistic, eating smaller snails.
Lymnaea stagnalis lays large gelatinous egg-masses on weeds and other objects in the pond. These egg masses measure between five and six centimetres in length, and can contain as many as 50 to 120 eggs. The size to which a specimen will grow is dependent upon the volume of water in the pond; individuals grow larger in big ponds. Young specimens are slender and have more translucent shells than mature snails.
Although Lymnaea stagnalis often comes to the surface to take in air into a respiratory cavity, when the pond becomes covered in ice or when the snail moves to deeper water in winter, it is able to take in oxygen from the water through the skin. The wide tentacles play a key role in the intake of oxygen; the surface of the tentacles is covered in tiny hair-like structures known as ‘cilia’ which function to increase their surface area, thus increasing the intake of air.
Lymnaea stagnalis is a simultaneously hermaphroditic species and can mate in the male and female role, but within one copulation only one sexual role is performed at a time. Lymnaea stagnalis perform more inseminations in larger groups and prefer to inseminate novel over familiar partners. Such higher motivation to copulate when a new partner is encountered is known as the Coolidge effect and has been demonstrated in hermaphrodites firstly in 2007. Lymnaea Stagnalis can reach ages of 6 or 7 years, although relatively few reach this age.
Lymnaea stagnalis tolerates wide range of the water parameters: temperature 0°C – 30°C, water hardness 0 – 30 dGH, acidity pH 5.0 – 8.0.
These Great Pond Snails are suitable for your pond or aquarium. They make a good clean up crew eating any left over food and algae. The snails we offer have been bred in a controlled environment and have not been sourced from a wild water source. Please carefully acclimatize the snails to their new environment. The supplied snails vary in size approx from 10 to 30 mm.