Pest Snails: How To Identify, Treat, and Remove Them From Your Aquarium

Family at aquarium
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Written by Kristin Hitchcock

Published: September 16, 2023

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Aquarium enthusiasts work very diligently to keep their aquariums in a careful, harmonious balance. However, the appearance of unwanted inhabitants, particularly pest snails, can disrupt this harmony. These uninvited guests are often introduced unintentionally, and they can multiply extremely quickly, compromising the health of the whole tank.

As their name suggests, pest snails are not planned residents of an aquarium. They may hitchhike into a tank through various means, such as a newly acquired plant, aquarium substrate, or even the shells of other aquatic residents. They can be an unwelcome surprise a few weeks later when your tank is suddenly full of snails.

To keep your aquarium healthy, it’s important to identify and remove pest snails as quickly as possible.

These snails can rapidly reproduce and eat practically everything if left unchecked, leading to overpopulation and a desolate aquarium.

In this article, we’ll discuss identifying these snails, including an outline of several common species. Then, we’ll look at how to get rid of them.

Types of Pest Snails

There are many types of “pest snails” that you may find in the aquarium world. Not all snails are considered pests. Some can actually be beneficial. However, pest snails reproduce very quickly, leading to an infestation if left unchecked. Beyond that, pest snails differ in appearance, size, and behavior.

Therefore, you can’t just look for one set of characteristics when identifying a pest species. You have to look at several.

Ramshorn Snails (Planorbidae family):

Ramshorn snails are named for their coiled, spiral-shaped shells, which resemble a ram’s horn. They can come in many different colors, including red, brown, and black. These snails breed very quickly and can overrun an aquarium if you aren’t careful. They’ll feed primarily on uneaten food, decaying plants, and algae.

Malaysian Trumpet Snails (Melanoides tuberculata):

Malaysian trumpet snails have very elongated shells with spiral ridges. They’re usually a darker color, like dark brown or blackish. They tend to burrow into the substrate of the aquarium, where they consume detritus. They can also help aerate the substrate, which isn’t a bad thing. However, their population can explode under favorable conditions.

Pond Snails (Lymnaeidae family):

Pond snails are exceptionally small – only about 1 cm in size. They have conical or pear-shaped shells that can be brownish or even translucent. They feed primarily on leftover food and algae. With enough food and the right nutrients, they can multiply fairly quickly.

Why Does it Matter?

Different pest snail species will have different characteristics and habits. Therefore, they need to be handled in different ways. What works for one species won’t necessarily work for another. It’s crucial that you figure out exactly what pest species you’re dealing with before you start making treatment decisions.

How to Identify Pest Snails

When telling different pest snail species apart, there are a few characteristics you can look at. The snail’s shell, size, and color are the most telling features. Here’s a quick table to help you distinguish different species:

SpeciesShellSizeColor
Ramshorn SnailsFlat, coiled shells1-2 cmRed, brown, black
Malaysian Trumpet SnailsLong, conical shells1-2 cmDark brown or black
Pond SnailsPear-shaped shells1 cmBrown or translucent

Signs of Infestation

Sometimes, you may not notice the snails themselves. They’re very small, so it can be easy to overlook them in a larger aquarium.

However, there are some signs that you have a pest snail on your hand, even if you haven’t identified the specific species. For instance, if you have snails in your aquarium, and they suddenly start breeding a lot, it may be a sign that you have a pest snail species.

Pest snails feed on algae and leftover fish food. If you see snails actively grazing on surfaces in your aquarium, especially on plants and glass, it’s an indication of their presence. However, other snails graze in these areas, too, so you can’t use this to identify the exact type of snail.

However, you can use it to identify if you have snails. Look at where the leftover food and algae accumulate in your aquarium for signs of snails.

You can also look for signs of snail eggs. However, this can be more challenging. Pest snails lay translucent, gel-like egg masses on aquarium surfaces. These clusters can be hard to spot but are usually found on plant leaves, decorations, or glass. It can be harder to find the eggs of other species, though.

Pest Snails vs. Beneficial Snails

Honestly, there aren’t many differences between a pest snail and a beneficial snail. Pest snails simply tend to breed faster. Therefore, they’re more likely to overpopulate and out-compete the other species in the aquarium.

Nerite snails and Mystery snails are examples of beneficial snail species. These snails can assist with algae, but they don’t tend to overpopulate.

The only way to know if you specifically have a pest species or not is to identify the exact type of snail. You can wait to see if they begin to populate very fast, but you usually want to start controlling their population before this happens.

The Dangers of Pest Snails

While pest snails may seem harmless at first, they can pose a huge danger to your aquarium. There are several drawbacks you should consider before allowing these snails to be.

Pet snails reproduce rapidly, which is their main danger. Their population can explode quickly in a considerably short period. If they multiply too quickly, they can compete with other inhabitants for food. In many cases, the pest snails win this competition, killing the other inhabitants of the aquarium.

Pet snails often consume algae and uneaten fish food. However, their appetite can be voracious, leading to them consuming other animal’s food, too. Eventually, they may affect the health and growth of the other fish.

They can also deplete the oxygen levels within the tank. A densely populated snail colony needs a lot of oxygen. In a tank, the oxygen level can only regenerate at a fixed rate. Therefore, if the snails start consuming more oxygen than it is replaced, the oxygen levels can be depleted.

While snails don’t usually harm plants when kept individually, they can graze on aquarium plants when other food sources are low. In a very populated colony, the snails can weaken plants and inhibit their growth. Some species may burrow into the substrate, disturbing the roots and eventually causing the plants to die.

As snails consume food, they also produce waste. When allowed to reproduce, pest snails can produce more waste than the aquarium can handle, leading to elevated ammonia and nitrite levels. These elevated chemicals can harm other aquarium inhabitants.

Dead and decaying snails can also release organic matter into the water. This can further lead to ammonia spikes and poor water quality.

Pest snails can also carry diseases and parasites, which they can pass to other aquarium inhabitants. They may even serve as vectors for other pathogens, introducing health problems into the fish of your aquarium.

Preventing Pest Snail Infestations

Prevention is the best strategy when it comes to pest snails. We recommend taking proactive steps to minimize the introduction of pest snails in the first place.

The best way to do this is to quarantine new plants and animals. Pest snails often piggyback on something else. If you add new aquatic plants to your aquarium without rinsing and quarantining them, then you risk introducing pest snails into your main tank.

The same is true for fish. New fish and invertebrates can both harbor small snails or eggs. It’s important to keep them in a quarantine tank for a few weeks so that you notice these snails before you accidentally put them into your tank.

Maintaining your tank correctly can also help. Regularly clean the substrate, perform water changes, and remove uneaten food. This reduces the excessive nutrients that can fuel snail growth and reproduction.

Ensure that your water’s parameters are within the range needed for your tank, as this can also deter snail proliferation.

Only feed your fish what they can consume in a few minutes. Overfeeding can lead to excessive food that can trigger an explosion in the snail population. In many cases, it’s this excess food that fuels the growth of the snails, so eliminating it will prevent the snail population from exploding.

You can also use automated feeders or feeding rings to ensure the food is consumed and doesn’t accumulate at the bottom of the tank.

When setting up an aquarium or replacing the substrate, you should opt to use a snail-free substrate that will minimize the chance of snail introduction. Also, inspect new decorations, equipment, or other items before you place them in your aquarium. Everything should be rinsed and possibly quarantined to prevent snails from being introduced to the aquarium.

Treating and Removing Pest Snails

Assassin Snail

Assassin snails primarily consume other snails, allowing them to control the pest snail population.

©iStock.com/M-Production

If you do discover pest snails in your aquarium, it’s important to treat them promptly. Once the population explodes, they can be much more challenging to get rid of. You do not want to wait until there is simply too many snails to remove.

The simplest method is to manually pick the snails from the aquarium. You can use a net or your hands to carefully remove the snails. However, this is only really practical with a small infestation.

You can also use commercial traps to lure and capture the snails. These traps often use bait to attract the snails so that you can remove them more efficiently. However, they may also attract species you don’t want to remove, so keep that in mind.

Consider using a gravel vacuum to remove snails and their eggs from the substrate. Often, this can remove many of the snails, but it won’t necessarily remove all of them.

Copper-based medications can be effective in killing snails. However, they are also toxic to several other fish and invertebrates. Therefore, it’s important to consider the other animals in your aquarium before using them.

You can also use aluminum sulfate, which disrupts pest snails’ membranes. It’s best to remove snails and affected plants, treat them in a separate container, and re-introduce them to the aquarium once the treatment is complete.

For long-term control, we suggest introducing biological controls to the aquarium. Assassin snails are natural predators of most pest snail species. They can help to keep their population in check. If you introduce these into your aquarium, they will actively hunt and consume other snails.

Some species of botia loaches, like the yoyo loach or clown loach, enjoy snail hunting. Adding them to your tank can help control a snail infestation. In larger aquariums, you can introduce goldfish and certain cichlids that are known to feed on snails.

Alternative Uses for Pest Snails

While the primary goal is often to eliminate pest snails from your aquarium, there are alternative approaches to consider before resorting to complete eradication. These options are considered more ethical, as they make some use for the snails.

Some fish species eat pest snails. You can try feeding the snails to these species so that they don’t go to waste. Adding these fish to the aquarium can also be helpful, as we’ve explained above.

Certain invertebrates, like crayfish, also relish snails. Adding compatible crayfish to your tank can help keep the snail population in check.

Even if you don’t have these fish, you may be able to find someone who does. Consider donating these snails to them for free or a nominal fee so they can use them as a food source for their fish.

Some local pet stores may be willing to take excess snails, as well. They may feed them to their fish or offer them for sale as a food source for others’ fish.

If none of these options are viable, you can consider composting the snails. They can be composted into any usual compost pile. This process allows the snails to be broken down and their nutrients to be utilized.


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About the Author

Kristin is a writer at A-Z Animals primarily covering dogs, cats, fish, and other pets. She has been an animal writer for seven years, writing for top publications on everything from chinchilla cancer to the rise of designer dogs. She currently lives in Tennessee with her cat, dogs, and two children. When she isn't writing about pets, she enjoys hiking and crocheting.

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