The Great Pond snails (Lymnaea stagnalis) are one the largest aquatic snail species in fish or shrimp keeping hobby. They belong to the family of so-called “Mud snails” (Lymnaeidae). The common Pond snails are considered “Pest snails“ by many aquarium owners. It means that they do not require any special care in your tank. Nonetheless, if you want to improve your knowledge base about them, this guide is for you.
Pond snails are extremely hardy animals. They can live and thrive in conditions that proved fatal to their tank mates. Basically, they have a reputation for being bombproof.
In most cases, aquarists do not put Pond snails in their tank. They usually come as hitchhikers on aquatic plants (do not forget to quarantine any plant, read more here), driftwood, stones, decorations, etc. Next, they make themselves at home in your tank.
Quick Notes about Pond Snails
|Common names||The Great Pond snail, The Giant Pond snail|
|Scientific name||Lymnaea stagnalis|
|Tank size (minimal)||1-gallon (~5 liters)|
|Size||2.5 – 7 cm (1 – 3 inches)|
|Temperature||0 to 33 C (~32°F – 90°F)|
|Optimal PH||6,5 – 8 (6 – 9)|
|Optimal GH||4 – 8 (0 – 30)|
|Optimal KH||2 – 8 (0 – 25)|
|TDS (optimal)||150 – 250 (50 – 500)|
|Nitrate||Less than 100 ppm|
|Diet||Omnivore / Algae eater|
|Life span||up to 3 years|
Pond Snail and Natural Habitat
Pond snails occur commonly in European lakes, ponds, marshes, and ditches, and can be easily collected in the field. Nowadays, they can be also found in northern Asia, Northern America, Tasmania and even New Zealand.
These snails prefer calm, still water with lots of plants, or very slow-moving rivers and streams.
Note: Their Latin name “Stagnalis” suggests, that this species prefers stagnant water.
Pond Snails Description
Pond snails have sharply tapered shells with wide openings. The shape and size of the shells are obviously regionally different. The form of the shells also dependent on external environmental influences, and age of the snail. In general, their shells have from 2 to 6 weakly convex whorls.
The main color of the shells is yellowish-brown with different variations (light-brown to dark-brown). In some cases, the shell can have tiny dark spots, however, there are usually no obvious markings.
They have thick, triangular-shaped tentacles.
Pond snails can be very large. According to different observations, Pond snails can grow to be somewhere between 1 and 3 inches (3 – 7 cm) in total length.
Note: In freshwater tanks, they usually do not grow more than 1 – 2 inches (2.5 – 5 cm).
This snail species does not have a lid (operculum).
In captivity, Pond snails usually live for about 1.5 to 3 years. They mature sexually at an age of 2.5–3.5 months depending on the temperature and feeding regimen.
Pond snails are bimodal breathers, it means that they can get oxygen either through cutaneous respiration (i.e. directly through the skin) or through aerial respiration via a rudimentary lung (i.e. gas exchange with the atmosphere).
To perform aerial respiration, the snail must surface and open its breathing pore while contracting and relaxing the appropriate respiratory muscles.
Interesting fact: Laboratory-reared Pond snails that have never experienced a natural predator (crayfish) are still capable of detecting and responding to the presence of a historically sympatric predator.
Pond snails and Bladder Snails
There is a lot of confusion and misunderstanding in our hobby. Aquarists often do not see (or do not know) the difference between “Pond snails” (Lymnaea stagnalis) and “Bladder snails” (Physella acuta – read more about them) and use them as synonyms.
|Pond snails||Bladder snails|
|Size||1 – 3 inches (2.5 – 7 cm)||Up to 0.6 inches (~1.5 cm)|
|Shell form||They usually have shells that spiral to the right||They usually have shells that spiral to the left|
|Shell color||Brown variations||Pale in color with markings (spots)|
|Tentacles||Thick and triangular shaped||Thin and short|
|Reproduction||Prolific egg layers||Extremely prolific
Pond Snails Diet
Pond snails are omnivorous eaters, including both plant and animal material in their diet. In the wild, they fulfill a pivotal role in the consumption and decomposition of aquatic plants (both living and dead).
According to experiments, the most common food is detritus (50 – 90 %) followed by algae (25%). Therefore, in freshwater tanks, Pond snails can also be your cleanup crew.
Note: There are reports that Pond snail may occasionally be cannibalistic, eating smaller snails.
Important: I would not say that Pond snails are plant safe. Although they will not eat plants voraciously (like Marisa Cornuarietis Snail, read more about it), they will still damage them (usually eat holes in the plants, Pond snails prefer the soft parts of the leaves over the midrib). Of course, you can distract them with green food for some time but it will not solve the problem.
You can read about it in my article “How to Blanch Сucumbers and Zucchini for Shrimp, Snails and Fish the Right Way”.
Feeding Pond Snails
It is extremely easy to feed them in the tank. Basically, they will eat absolutely everything you give them. Therefore, if you have an outbreak of snails, it means that you feed way too much!
Frankly saying, I can see one reason to feed them on purpose – as food for pufferfish, crayfish, birds, etc.
Note: Pufferfish needs to eat animals (snails, shrimp, crabs, crayfish) that have a hard sort of shell on them.
Keep in mind that different studies have shown that metabolic rates and consumption increase with a temperature rise. So, if you want the snails to breed them like crazy, increase the temperature and feed the tank very heavily.
However, I would recommend doing that in the snails’ tank only! The point is that leftovers can lead to the buildup of toxic compounds. Even worse, it can also cause an outbreak of infection. Scutariella Japonica, Planaria, Vorticella, Hydra, and Ellobiopsidae or Green fungus can become a very serious problem for you and your fish and shrimp.
Interesting fact: Pond snails can eat Hydra in the tank. Of course, they will not remove them completely (because Hydra is not their main food source), but they will help you to reduce the hydra population.
Keeping Pond Snails
Pond snails are very extremely easy to care for and can be kept in various kinds of water parameters. In the wild, they live in puddles and mucky ponds, which do not have any circulation. They are very resilient creatures.
Pond snails do not care about the tank size. You can keep them in a 1-gallon tank (~5 liters) or little buckets. They can be OK even without filters, pumps, heaters, etc. However, in this case, you will have to do at least regular water changes. Although pond snails are super hardy, they are still mortal. 🙂
They have no preferences and can tolerate even very soft water for some time. According to the study, temporary (short-lasting) pH changes can be tolerated in a wider range – up to pH 3.5! However, if your water has pH less than 6.5 for weeks (months), Pond snails will have problems with shell formation. At low pH calcium uptake is particularly difficult, which slows down and disturbs the formation of the shell.
In addition, Pond snails will not feel stress at both 15C and 25C. They simply do not care because, in the wild, they can easily overwinter in ponds that do not freeze to the bottom.
Note: I would still recommend using the simplest sponge filter in their tank setup. They are living things, after all. Even if you are planning to breed them as food for your fish, it will greatly increase their number.
Calcium and Pond Snails
Like all snails and shrimp, Pond snails need calcium either in their diet or in the water (ideally, both) to make their shells hard enough to sustain their body. They have shells, which consist of calcium.
Therefore, add enough calcium (eggshells, antacids, cuttlefish bones, etc.) and your snails will be fine.
|I highly recommend reading my article “How to Supplement Shrimp and Snails with Calcium”.|
Breeding Pond Snails
Pond snail is a hermaphrodite species that can self- and cross-fertilize (mixed mating system) with a preference for outcrossing and that experiences low inbreeding depression.
Adult snails can mate in the male and female roles. During mating behavior, one snail acts as the male and the other as the female. When the snail plays the male role, it climbs on the shell of the prospective female, moves over the shell in a counter-clockwise direction until he reaches the area of the female gonophore. The whole mating behavior can last for several hours.
Interesting facts: The younger snail tends to mate as male, whereas senior snails act primarily as female. Biologists believe that there are two explanations here. First, senior (bigger) snails have more resources to invest in reproduction (larger snails produce more eggs). Second, in younger snails, the size of the prostate gland increases faster.
However, it does not mean that their roles are restricted. Observations of spontaneous matings show that snails of 18 mm are already able to mate as male as well as female.
They can donate and receive sperm relatively frequently (at least once per week), and received sperm can be stored and used for approximately 3 months.
Egg masses are produced at a relatively high rate (more than one mass per week). Pond snails lay eggs in cocoons below the waterline.
During oviposition (egg-laying), masses containing 50–100 eggs embedded in a gelatinous mass, from which juvenile snails of adult form emerge following about 10 days of intracapsular embryogenic development, without any free-living larval stages.
In the eggs, these embryos metamorphose by approximately day 5 post-oviposition. At this early stage, they become shell-bearing snails that will be fully-developed snails upon hatching.
Pond snails are not complicated or difficult to keep. Actually, they are super easy to care for. They accept a variety of food, can be kept in various kinds of water, and breed easily.
Pond snails are usually not welcome in planted tanks because they feed on aquatic plants.