What are Pest Snails in an Aquarium and Are They Bad?

Aquatic snails are common in the aquarium hobby, and if you decide to have a planted aquarium, they are almost unavoidable. Snails often hitchhike on live plants and find themselves as uninvited guests to your fish tank.

But are snails a simple pest to be removed, or are they a blessing in disguise?

Depending on where you look, you may find conflicting information on snails, with sources conflicting with each other stating that snails are bad or good.

We aim to settle this conflict by giving a balanced view on snails, and how to properly manage them.

Types of pest snails in aquariums

There are around 4,000 different species of freshwater snails!

A couple of these snail species have found themselves in the aquarium hobby, and over years, have lived within peoples tanks.

From this, they have hopped from tank to tank and carved themselves out a niche surviving in captivity, and have essentially domesticated themselves!

These hitchhiker snails are labelled as pest snails by many, as they are unwanted – people usually do not intentionally introduce these types of snails to their tank.

As there are so many snail species, we cannot cover them all, but we will do our best to cover the ones that are commonly encountered by the majority of aquarium keepers.

Bladder snail

These are perhaps the most frequently encountered freshwater snail, they have the appearance of a golden yellow coloured shell, usually accompanied with pale or dark bronze speckles on them. They have pale skin, and have a shell shape similar to that of a tear droplet. They are small, only reaching around 1cm in size.

These snails are detritivores and do not eat healthy live plants!

They will eat fish food, decomposing organic materials, dead or dying plant leaves, fish waste, carrion and most types of algae.

Bladder snails will breed fast, but this can be easily controlled by reducing the amount of food given to the tank. These snails lay eggs in small gel-covered clusters which are commonly fed on by most fish.

Bladder snails also make an excellent food source for many loach and pufferfish species!

Pond snail

Very similar to the bladder snail except it gets larger, about an inch or so, they are usually dark brown in colour, with some variations of gold, red, bronze and black.

Both pond snails and bladder snails can live in cold water or tropical water, meaning they can be kept outdoors in ponds.

Both of these snails are good clean up crew, and help to reduce ammonia and nitrites by decomposing organic material!

Ramshorn snail

The common ramshorn, not to be confused with the columbian ramshorn or flat ramshorn snail, is small, reaching a max size of around 1 inch. They come in all colours, red, pink, green, gold, brown, blue, black, white etc.  

They are the classic snail shape, with the round curled shell.

These live similar lifestyles to bladder snails and pond snails, eating the same foods and reproducing in the same way.

Something interesting about these snails is that they are all hermaphrodites, meaning they have both male and female reproductive organs.

This works well for them as it means any two snails can mate, they don’t need to look specifically for a male or female snail! They do however, still have to mate with another snail and cannot self fertilise.

Flat ramshorn snail

Not as common as its larger cousin, this snail is near enough the same but smaller, only reaching sizes of around 2 mm. These guys have a flatter shell and are a golden bronze colour.

Malaysian trumpet snail

These are the personal favourite of our writer Lewis – they are a bit different from the other snails on this list.

They are usually pale brown in colour, with black skin. They have a cone shaped shell and spend most of their lives on the bottom of the tank.

These snails burrow under the substrate and are mostly nocturnal. They feed on algae and detritus, and are much better at breaking down organic matter than the other previously mentioned snails.

They do not eat plants, unless they are dead or dying.

These snails also have a different reproductive cycle, they actually give live birth instead of laying eggs, making them much more successful in an environment with fish.

They are also hermaphrodites and have the ability to clone themselves – this means that only one snail is needed for them to breed!

This makes them the fastest reproducing snails from this list, and the most likely to overrun your tank.

Where do aquarium snails come from?

As mentioned, snails come in on plants. They can also come in from any second hand decor from a tank that houses snails, particularly the sand or filter contents, where baby snails live.

Their origins come from the lakes, ponds and rivers which they inhabit in the wild. Often when collecting fish and plants, snails will be accidentally caught up, shipped overseas and eventually end up in someone’s aquarium.

Are aquarium snails nocturnal?

Yes, aquarium snails are nocturnal. They don’t have a typical 24 hour sleep cycle, so they may be seen out during the day as well.

Do snails produce ammonia?

No, snails do not produce ammonia in a fish tank, unless they are dead. Snails are actually really great at reducing ammonia in a fish tank by cleaning it!

Why are baby snails appearing in my fish tank?

Baby snails will appear in your tank if eggs or adult snails have been introduced to your tank and bred!

If you see baby snails, then it means that your tank is an ideal environment for them to live and breed in!

All tank animals will breed to the amount of food available to them.

If you find that you had no snails at all, and then suddenly have thousands of snails invading your tank, it means that there is enough food in the environment to support them.

The fact that there are so many snails means that you are either feeding too much or there is a plentiful food source for them to subsist on.

This is the ecosystem balancing itself out, they are actually doing you a huge favour by keeping your tank clean.

In essence, if your tank has 5,000 snails, then it must need 5,000 snails to consume the waste!

If you reduce your feeding, you will see this number go down, as the snails will die off and the population will stabilise.

Are pest snails bad for your aquarium?

Snails are not necessarily bad for your aquarium.

In fact, they can be highly beneficial. They do however, have some downsides to them:

  • They reproduce fast and can quickly overrun your tank
  • Your fish could try to swallow them
  • They consume oxygen and produce their own waste
  • They can be unsightly if you don’t like snails

This is as far snails go in terms of causing issues.

Are there any beneficial aquarium snails?

All “pest” snails are beneficial; in fact, they create more benefits for your aquarium than they cause issues!

Firstly, they assist in the decomposition of waste, any detritus, uneaten food, dead plants or fish waste left in the tank produces ammonia – this is harmful and can kill your fish.

However, snails will eat all of this waste and convert it to their own faeces, snail waste is extremely broken down nutrients and is very very easy for bacteria and plants to utilise, making the denitrifying process significantly faster and more effective!

This snail waste is also the perfect food for infusoria, which fry feed on, making them ideal candidates for fry tanks too!

Snails are excellent clean up crew as they will eat anything; even very far decomposed food, which fish and other animals cant digest. 

Due to their small size and sticky foot, snails can also get within all the nooks and crannies within your tank, which would normally build up waste and cause an ammonia spike.

Snails also eat algae, keeping your tank clean!

They also clean the leaves of live plants, preventing algaes from swamping and killing them.

✅ If you like snails, then you are in luck, as they can add quite an authentic and natural look to your tank, with some species and breeds having spectacular colours, such as the ramshorn snail.

Snails can also live in nearly every environment due to their hardy nature and tough shell! They can live with peaceful community tanks, to breeding setups, to ponds, to display tanks, to aggressive fish tanks!

Snails which burrow also aerate the soil, preventing toxic gases from building up, and they also provide nutrients to plant roots!

Should I remove pest snails from an aquarium?

small snails sat inside a see through container

If you don’t like snails, and don’t want them in your tank, then you can remove them.

Just know that this isn’t an easy task, especially if the snails are breeding in your aquarium.

Although you might remove them everyday, they may still keep coming back.

But should you remove them? This is really down to your personal preference, however, while snails have a few minor downsides, they have plenty more upsides.

It is commonly agreed upon that keeping fish as natural as possible is a good recipe for success, and snails add to this, as they are a naturally occurring part of the aquatic ecosystem and fill out their roll perfectly.

Can aquarium snails kill fish?

It is unlikely that an aquarium snail would kill a fish – they will not chase or actively harm your fish. If there is a dead fish left in your tank however, they may begin to eat it.

How do you get rid of pest aquarium snails?

If you still want to remove snails by this stage, then there are ways to do it, however, there are right ways and wrong ways to go about it.

❌ The first method people use is to crush the snails with their thumb when they see them – this is probably the worst way to get rid of snails as it only adds to the issue.

Whenever you kill a snail, its body sinks to the bottom and is then eaten by other snails, who will then breed even more because of the new food source, creating an endless cycle.

❌ The next thing you can do is bring in a fish that will eat the snails – this again is a poor decision. While it may fix your problem, it creates a host of other issues for you and your fish.

First off, we don’t endorse the idea of a “work fish”. This is a fish specifically added to the aquarium to do work, in this case it would be a loach or pufferfish. These fish have specific care requirements and dont always match with your tank’s water parameters, conditions and other inhabitants.

You should want to keep the fish themselves with no ulterior motive in mind; this way, they can receive the best care possible and can work in your favour.

Clown loaches are often sold in pet stores as “snail eaters”, however, if a petstore representative tries to talk you into getting a clown loach, don’t do it! Unless you are prepared to keep a fish which grows up to 3ft, is extremely active and only likes to live in large schools.

A better alternative would be the dwarf chain loach, yoyo loach, dojo loach or burmese border loach as these don’t get as large, and will eat snails readily, but they still have specific requirements you should look into first.

The assassin snail can be added to kill other snails, however, they aren’t killing machines. They hunt and eat when they are hungry and won’t fix your problem overnight.

They also breed themselves, (although not as fast). If you want to get rid of snails, the last thing you’d want to do is add more snails!

❌ Another method you could use is chemically poisoning the snails. These chemicals do exist, but be very careful when using them, as dead snails produce ammonia, and killing thousands of snails at once will definitely crash your tank and could kill everything in it.

So we don’t really recommend using chemicals to kill your snails either.

The best method to get rid of snails is to remove them by hand, while also feeding less. As previously stated, snails will breed to the amount of food available to them – if there is no food, then the tank cannot support a growing population of snails.

Removing them by hand everyday will slowly but surely get rid of them, or at least reduce their numbers so much that they do not cause any problems.

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