6 Reasons Why Trapdoor Snails Are Good For Your Pond

Have you ever wondered what the snails in your pond are up to? Perhaps you thought about removing them altogether? Then just wait a minute; they are actually pretty helpful…

In short, freshwater snails are great for the ecosystem of your pond. As such, Trapdoor snails keep pond water clean, take out the trash, eat organic leftovers, scrub the surface bottom, manage pond algae, reproduce at a slow rate, and reduce levels of ammonia.

With over 43 thousand different species divided on both land and water, they belong to the Gastropoda family and are believed to be over 500 million years old. Snails have been doing great things in ponds for ages! Yet perhaps all this sounds too good to be true. So let’s have a closer look at these little scavengers together.

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Snails Keep Pond Water Clean

For all those who are fond of their pond, the main goal is to keep your tank clean and safeguard and sustain a healthy environment going forward.

As snails can live up to seven years, with Trapdoors up to ten, we might argue that they like to keep their surroundings clean. And indeed, snails are keen promoters of clean water.

Of course, not all snails thrive in water. Thus leaving the land snails aside, we are here predominantly talking about freshwater snails. Also called aquatic snails, or more commonly referred to as pond snails. Furthermore, one of the biggest and, therefore, most effective helpers amongst the pond snails is the Trapdoor snail.

Interesting fact: Most snails tend to be hermaphrodites, meaning they can either be male or female. What’s even more peculiar is their ability to reproduce without mating. As they do not need to mate, self-fertilization is made possible. However, their lack of need to mate doesn’t mean they don’t actually do so when possible. Indeed, they also like company. Interestingly enough, Trapdoor snails are amongst the exception and are actually non-hermaphroditic.

If you are wondering how you might invite these snails to come to visit your pond, there is no need to worry; all it takes is to maintain healthy activity within your pond. Make sure there is enough food around for everyone, and the pond snails will tangle along.

But wait a minute, how do snails actually help clean the water?

Snails Take Out The Trash

Snails will consume the leftovers, and they will scavenge around and eat their share of decaying organic material, such as plants and algae. Indeed, they clean what others leave behind. Therefore, pond snails are often called decomposers.

Trapdoor snails in specific tend to grow twice as big as the average freshwater snail, meaning they can consume more, resulting in more trash being taken out. Therefore, Trapdoor snails are the most effective of them all.

Not only do they eat decaying organic material from plants, and algae, they also eat leftovers from fish food. Although this will assist against overfeeding your fish, we should not expect too much of our little helpers either. We should thus remain aware of how we feed our fish.

It is also good to know that we can actively improve a Trapdoor snail’s diet, by supplementing their intake of waste, with green vegetables such as lettuce, kale, spinach, and cucumbers. They are just fond of calcium!

Overall, Trapdoor snails assist in cleaning your tank, thereby reducing your pond’s maintenance requirements. This will save you some time and effort; as a result, meaning you can further improve your pond.

Snails Scrub The Bottom Clean

Scrub, scrub, until it’s clean!

In a well-populated and thriving pond, various pieces of waste will find their way to the bottom of the tank. Whether pieces of fish food, decaying parts of plants, and other organisms, all will come to reside at the bottom of the pond.

Trapdoor snails are herbivorous and enjoy a cold feeding session during night-time. They feed on algae and decaying organic material from plants, and fungi. As such, Trapdoor snails are little scavengers that will scrub the bottom of your tank, providing us with a convenient cleaning service indeed.

Up close shot of trapdoor snail, brown spiraled shell.

Snails Manage Algae

Pond snails go around the edges of your pond; they eat algae off the bottom, rocks, and sides. Trapdoor snails are also friendly to plants, meaning they will clean the stems and leaves without eating or damaging the actual plant. Indeed, they will only eat decaying plants.

Not all pond snails will consume algae as effectively as a Trapdoor snail. Therefore this is truly where the little scavengers stand out, as they are known to be the biggest algae eaters in the family.

Furthermore, Trapdoor snails are careful when it comes to grazing algae of a plant. Indeed, many are found of Trapdoor snails because they do not harm the plants in the pond; they merely scavenge around the stems and edges whilst only actively feeding on decaying plants.

Interesting fact: Snails are also the most dominant grazers of algae and aquatic plants outside our ponds, in lakes, and rivers across North America.

Snails Reproduce Slowly

It is important to maintain a balanced ecosystem within your pond. So making sure there aren’t too many snails in your tank is key! If not, they might prevent new plants from thriving. Therefore, it is advised to keep track of your snails.

Luckily for us, Trapdoor snails reproduce rather slowly, meaning that you won’t need to worry about the amount of snails in your pond, to begin with.

Unlike most snails, Trapdoor snails are not asexual, meaning they need to breed and find a mate. Therefore, their chances at reproduction are already reduced, to begin with.

In case there are still too many snails within your pond, it is best you try to remove them with a skimming net instead of making your hands dirty.

If you’re interested, you can take a gander at the Aquascape Pond Shark Net Skimming Net.

Interesting fact: Trapdoor snails are also referred to as Chinese mystery snails. You’ve guessed it! Before settling in North America, Trapdoor snails were native to East Asia.

Snails Reduce Levels of Ammonia

Ammonia in your tank

Ammonia is an invisible killer for your pond. It is highly toxic and harmful to your fish. As such, it is better not to leave this hazard unchecked. But how does ammonia even enter your pond, to begin with?

In short, ammonia, a compound made of nitrogen and hydrogen, is released into the pond through waste. More specifically, it is spread through the breakdown of organic material. This includes various forms of waste and dirt, such as fish excrement, leftover food, dead plants, and decaying algae.

As snails are known to take care of waste, to some degree, they are part of what we call the Nitrogen cycle.

The Nitrogen Cycle

The Nitrogen cycle refers to the process that transforms ammonia into nitrate, which is eventually used to grow plants in your tank. However, a high level of nitrate in your pond will be harmful to the fish. Therefore it is advised to clean the water and reduce the amount of nitrate in your pond.

As snails assist in reducing waste, thereby cleaning water overall, they indeed are a plus when it comes to safeguarding a healthy nitrogen cycle. Although snails can surely not take up the job themselves, they are natural and convenient little helpers nonetheless.

Ammonia Testing Kit

Finally, if you are not entirely confident whether your pond is safe and are not quite sure about the ammonia levels within your tank, you may want to make use of an ammonia testing kit.

These tests will allow you to measure and monitor the levels of ammonia in your tank. Eventually, this can enable you to prevent harm from being placed upon your fish while assisting in the overall sustainability of your tank.

For more information concerning testing kits, you might want to take a quick look at the following product: The API Test Kit.

Finally, What Trapdoor Snails Won’t Do For You:

Although Trapdoor snails seem to present the perfect cleaning kit for your pond, there are some things they just aren’t fond of. Therefore, here are a few points to be aware of:

  • They do not eat fish waste.
  • They will not eat the sticky and dirty-looking pond scum, which is actually a mix of brown algae and waste.
  • They also produce their own waste. Therefore it is once again essential to keep track of the amount of snails that are cozily nestled within your pond.

Finally, some wild snails may find themselves hosting a parasite of sorts. Therefore, it is not advised to actively introduce new snails to your pond. Let them come to you instead.


Brönmark, C., & Hansson, L. A. (2017). The biology of lakes and ponds. Oxford University Press.

Dillon, R. T., Wethington, A. R. (2006). Freshwater Gastropoda. The mollusks: a guide to their study, collection, and preservation. The American Malacological Society, Pittsburgh.

Moriarty, D. J. (1997). The role of microorganisms in aquaculture ponds. Aquaculture, 151(1-4).

Oswald, W. J. (1995). Ponds in the twenty-first century. Water Science and Technology, 31(12).

Royal Horticultural Society. (2021) Snails, UK’s leading gardening charity.

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  1. I have a five acre pond and am looking for an inexpensive and natural way to clear up the water. I live in GA so I know the bottom is probably red clay. I have a lot of trees around and the leaves end up in the water. Do you think snails would be a good way to go?
    Thank you,

    1. Great question – while they’re definitely eat some of the algae, the snails probably won’t clear up the entire water to get it to the point you’re expecting. They’re great for the overall ecosystem, though. They will eat much more organic matter than just algae, and skip some of the bad kinds.

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