Pond Snails: Good or Bad for Your Pond?
by Tory Jon | Last Updated: January 01, 2024
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If you’ve ever tried to maintain a garden, you've probably had some sort of interaction with snails.
In most cases, garden snails can be described as a nuisance, and most gardeners don’t want them in their garden.
Like garden snails, pond snails are a part of the gastropod family, but are they as much of a pest as their garden cousins?
Let's take a closer look at the different types of pond snails and learn whether they are good or bad for your pond.. and much more!
Pond Snails: Good or Bad For My Pond?
Like any animal, pond snails (Lymnaeidae) can play a part in the life of your pond, and they do offer some real benefits.
They can help remove unwanted infestations from your pond and deal with rotting matter, among other things.
On the other hand, snails prefer to feed on the good types of pond algae, not the bad blue/green algae. They may also eat your pond plants if there's not enough algae to consume.
Another potential drawback is the fact that snails can reproduce very quickly, leaving your pond overpopulated with snails that feed on the above!
With that said, lets break down the pros and cons of pond snails to see if they are right for your ponds ecosystem.
Pros
- They consume algae and can help keep it under control
- They also consume other pond debris that would end up in the pond sludge layer
- Snails are a viable option for those who want various types of pond life
Cons
- Prefer to eat the good green algae, instead of the bad blue/green (cyanobacteria) algae
- Can reproduce very quickly, crating an overabundance of snails in your pond
- A snail overabundance can lead to dead snails contributing to pond sludge, instead of helping
- May consume your healthy pond plants if there's a lack of algae to feed on
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What Do Pond Snails Eat?
As mentioned above, the diet of pond snails varies from species to species, but generally, freshwater snails will eat algae and leafy vegetation (just like their garden cousins). They can help control an overabundance of algae and will tend to eat this in preference to vegetation.
This means that even if you have a large number of plants in your pond, they will be safe, as the snails will concentrate on eating the algae instead. The snails will also eat some types of fruit and vegetables, including cucumbers, carrots, celery, and apples, but more importantly, they will eat dead fish and snails.
Rather than allowing this organic matter to sink to the bottom of the pond and decompose, it will be eaten by the living snails. This helps prevent the decomposition process from occurring, thereby reducing the chance of unwanted plants and pond weeds growing in the pond. This helps to maintain the overall health of the pond environment and makes pond snails quite beneficial to have around.
However, with all these sources of food available to the snails, you may need to be aware of how many snails live in your pond or water garden. If they reproduce too often, you may become overrun with snails who will end up eating the plants you do want to keep!
What Eats Pond Snails?
While snails will eat dead fish and other dead snails, the opposite can happen – some larger fish will eat pond snails. The most common pond fish, koi, do not eat snails, however, sterlet's will gladly feast on them.
Other natural predators include ducks, frogs, and turtles.
You can even fight fire with fire! In this case by utilizing Assassin snails to eat pond snails. Here's a video of an Assassin snail in action!
If you're trying to keep your snail population in check, using a natural predator can be helpful. However, if that’s not on your agenda, you'll want to ensure that all your pond animal species get along happily without eating each other!
Types of Pond Snails
There are a large number of species of pond snails, but here are a few of the most common.
Big Ear Pond Snail
Radix auricularia
A worldwide traveler, Big Ear pond snails originated in Europe and East Asia. The species has now spread across the globe to the USA and New Zealand and is a popular species to keep in many ponds.
They are generally most happy in clear still water, but will also survive in cloudy, murky pond water. They eat an assortment of green algae and enjoy decaying matter and even grains of sand. This makes them a useful species for clearing out unwanted elements from your pond or water garden.
They can grow up to around 3 inches in diameter, which is quite large for a pond snail.
Japanese Trapdoor Snails
Viviparus malleattus
Japanese Trapdoor Snails are another species that eat algae, again making them welcome in ponds to control unwanted growth. They also eat decaying matter and spend a lot of their time towards the bottom of a pond, happily disposing of leaves, uneaten fish food, fish waste, and other nuisances.
They are found all over the world and can survive in colder climates, even making it through the cold winter months unscathed.
One major difference between this species of snail and many others is that their young are born as snails, rather than eggs. This limits the number of snails that can be born, as egg yields are often much higher. Japanese Trapdoor snails are unlikely to be able to numerically overtake your pond environment because of this very reason.
Great Pond Snail
Lymnaea stagnalis
The Great Pond Snail, aka Lymnaea Stagnalis, is a species most often found in colder climates such as northern Europe, Russia, and Canada. Like the Big Ear, this species can grow to 3 inches in diameter, making them clearly visible in and around your pond.
They eat many different foods, including algae and vegetation. They don’t care if it is living or decomposing vegetation, as both suit their diet. Great Pond Snails are also known to eat small fish, other snails, and insect larvae, making them ideal for controlling unwanted bug populations.
They prefer to live in still or slow-moving water and are most comfortable with lots of vegetation in the pond area.
Dwarf Pond Snail
Galba truncatula
At the opposite end of the size spectrum are Dwarf Pond Snails, that grow to just over a third of an inch in diameter. Because they are so tiny, they prefer to live in smaller bodies of water, so if you have a small pond this may be the species for you.
Another worldwide traveler, the Dwarf Pond Snail is common in Europe, Asia, Alaska, and North Africa, showing an adaptability to many different climates.
Just like their larger relatives, they eat algae, decomposing matter (including leaves and fish), as well as available aquatic vegetation. Due to their small size, each snail will eat substantially less than their larger counterparts – but in a small pond, this can be a very good thing.
Ramshorn Pond Snail
Planorbidae
Ramshorn pond snails are often considered to be a nuisance rather than a benefit to the pond environment they live in. They lay eggs rather than birth live young, and so can rapidly increase in number.
They get their name due to the shape of their shell, which resembles a ram’s horn, making them easily identifiable. They are quite common and do have redeeming qualities – they eat all kinds of soft algae, and so can keep algae under control in your pond. They will eat vegetation, but if there are enough algae available your vegetation should be safe.
Ponds that are a little unclean and contain plenty of algae are an ideal environment for them, but they are also happy to live in clear water too – just watch out for your plants.
Ramshorn pond snail breathe through their skin and also with the use of a lung. This dual approach allows them to live in ponds with lower amounts of dissolved oxygen. Other species that breathe through gills would struggle to survive in such conditions.
Wandering Pond Snail
Radix balthica
The Wandering Pond Snail species grows to around an inch in diameter and eats plants, decaying matter, and algae. They are found across Europe and in parts of Asia in bodies of still water.
While they will help clear out your pond of decomposing matter and algae, their presence can be a worry if you have not purposely introduced them to the environment. Their favorite habitat is water that is full of nutrients, which often occurs when too much matter is decaying, or the pond has become contaminated with fertilizer or a leaking septic tank.
If they do appear, it is worth checking the quality of your water, as you will need to make sure it is suitable for the rest of the inhabitants of your pond. Excess nutrients may, in turn, lead to lower levels of oxidation, which is unhelpful for fish and even snails.
Other Snail Species
The snail species that have already been mentioned will be the most common and most likely to survive in a pond environment, but other species do exist. Some pond snails are tropical and need higher temperatures to live, and others can become a nuisance to the wider environment. If they are not native species, they may reproduce and spread, and potentially wipe out native populations, or at the very least upset the current ecosystem.
Keeping snails like these in an aquarium helps to limit their interaction with the wider environment, but proper research and care should be taken at all times.
A few of these species include:
Assassin snails – these snails are small but deadly. They are carnivorous and eat worms and other snails in the wild. In your pond, they might eat fish flakes and any high-protein supplements they can find.
Rabbit snails – small snails that eat algae and decaying plant matter. They often have spiral-shaped shells and prefer warmer water.
Tadpole snails – small snails that feed on algae and decaying matter, they are resilient enough to survive in even polluted ponds.
Mystery snails – these snails reproduce quickly, but do not lay eggs underwater – instead, they lay them just out of the water. They eat all kinds of decaying matter, leftover food, and anything else dead in your pond, but they won’t touch live plants. Mysterious!
Where To Buy Pond Snails
Purchasing pond snails can be a straightforward process, as there are several avenues you can explore:
- Local Aquarium or Pet Stores: These are often the most accessible sources for pond snails. Many pet stores that specialize in aquatic animals have a variety of snails, including those suitable for ponds.
- Garden Centers: Some garden centers, particularly those with a focus on outdoor ponds and water gardens, may offer pond snails for sale.
- Online Retailers: There are many online stores that specialize in aquatic life. These retailers often have a broader selection of snail species compared to physical stores. When buying online, make sure the retailer has good reviews and a policy for safe, live animal shipping.
- Aquatic Plant Suppliers: Suppliers who focus on aquatic plants often also sell pond snails, as the two often go hand-in-hand in pond ecosystems.
- Aquarium Clubs or Forums: Joining an aquarium club or participating in online forums can be a good way to find pond snails. Members often trade or sell various aquatic species, including snails.
How To Get Rid Of Pond Snails And Their Eggs
While there are benefits to having snails as you’ve seen above, there may be reasons that you don’t want them in your pond. If they have been accidentally introduced and are causing a nuisance, you’ll want to get rid of them as soon as possible.
Another problem you may encounter is that a large proportion of wild snails are hosts to numerous parasites. These parasites can easily be passed on to other animals and even humans, which may even cause death.
Obtaining snails from aquariums and breeders will dramatically lower the chance of the snail being a host.
To get rid of unwanted snails, the quickest method is manual removal of grown snails. This can be done by hand or by using a net. You may also be able to remove pond snail eggs in the same way, depending on the size.
If you are having trouble finding these aquatic animals, placing a lettuce leaf on the surface of your pond overnight will often attract a crowd of snails. This makes it a lot easier to remove them manually, as they are all together, and sometimes even attach themselves to the lettuce. Do note that using this method may attract snails that are beneficial and that you want to keep, so always proceed with caution.
You can also use a pond vacuum to increase the efficiency of the manual removal process, but this makes it less likely you’ll be able to spot any snails you want to keep.
An alternative solution to control them is to increase the number of predators in your pond. Frogs often enjoy a tasty snail treat, and Assassin snails are so-named because of their eating habits – they are carnivorous and are quite happy to eat snails that are smaller than they are.
Assassin snails do not reproduce quickly, only laying a few eggs at a time, so you won’t soon become overrun with them. Also, they need to breed in pairs, which can also limit their ability to reproduce.
A last resort may be to use chemicals to kill the snails. Remember that these chemicals can have an adverse effect on other animals in your pond – just because it’s designed to kill one type of animal it doesn’t mean it will leave others untouched.
A common chemical used to kill snails is copper sulfate, which also kills slugs. Used in the right quantities it works well, but is unfortunately toxic to fish and plants, and has the potential to destroy your pond’s environment.
Just remember, not all snails are bad – many provide great benefits to your pond and its ecosystem.
