How to Control Aquarium Snails

It happens to everyone eventually. You’re admiring your carefully maintained aquarium, when you notice something small on the glass. As you move closer to inspect it, you realize that it’s the bane of aquarium owners everywhere – a snail.

You have no idea how it managed to make its way into your pristine aquarium, but you know that if there’s one, there are probably dozens more hiding out of sight. And soon those dozens will mushrooms into hundreds until they overrun your aquarium.

The bad news is that once snails are established in an aquarium, they are almost impossible to get rid of (unless you use the nuclear option of using a snail killing product). But the good news is that with a bit of hard work on your part, they are relatively easy to control.

However, before you start culling the snails from your fish tank, you should first identify them, and see if they’re a pest or a boon to your aquarium. You can read the handy Aquarium Tidings – Snail Identification Guide here.

Prevention

The most common source of hitchhiker snails are live plants. Even if you can’t spot any snails on a new live plant, there may still be juvenile snails hiding among the leaves, or tiny snail eggs that are all but invisible to the naked eye.

This may not be helpful information if you’re already dealing with a snail infestation, but at the very least you can ensure that no new snails are introduced into your aquarium. This can be done by treating plants before you add them to your aquarium.

I have found that the most effective treatment to remove snails from live aquarium plants is to submerge them in a 5% chlorine bleach solution for between two to three minutes. Obviously, more delicate plants like water sprite should be on the lower end of that time scale, while hardier plants like Amazon swords can easily handle up to three minutes.

After the plants have been submerged in the bleach solution, they should be removed and carefully rinsed off in non-chlorinated water. While it’s not the most accurate way to determine if all of the bleach has been removed, I recommend smelling the plant afterwards. If any scent of bleach remains, it should be rinsed off again.

Proper precautions should be taken when handling bleach, and you can find chlorine bleach handling instructions here.

Manual Removal

It’s surprising that no one has invented a high tech method of removing snails from an aquarium, and the best way to remove them is still by hand. Just removing all of the visible adult snails from the aquarium will help to keep the population down, since these are generally the snails responsible for most of the breeding and damage to any live plants.

Removing snails by hand will put a decent dent in their population, but it should also be used in conjunction with a very basic snail trap. The trap is composed of an empty, clean mason jar with no lid, and a weighted piece of lettuce at the bottom of the jar. It should then be submerged in your aquarium, and left to sit on the bottom overnight.

The next morning, before you turn on the lights, you should remove the jar and the lettuce leaf. During the night, the vegetable will have become covered in snails, and by doing this regularly, the snail population will be kept in check.

If you are looking for a humane way to euthanize snails, they can be placed in a plastic bag in the freezer for several hours. If you’re less concerned with humanely disposing of them, the snails can be placed outside where they will dry out and eventually die.

Snail Removal Products

There are plenty of snail removal products on the market, but as previously stated, they tend to be the nuclear approach to the problem. Yes, they will most often clear out your snail infestation, but many of them are extremely toxic, and even the better ones will still be hard on your fish.

I would only ever recommend doing this if you’re very determined to remove your snails, and you are able to relocate your fish until the snail removal product has been filtered out, or the contaminated water has been replaced through water changes.

Snail Eating Fish

Many websites recommend introducing fish to an aquarium to control snails, but they never seem to mention the side effects of this strategy. Namely, once the snails are dealt with, what becomes of the fish?

Often the fish that are recommended are schooling fish and they don’t do well if kept individually, or even in a small group. And some of the recommended fish are wholly incompatible with almost every other possible tank mate.

If you are willing to deal with the issues that introducing a new fish to your aquarium entails, then there are several fish that are voracious snail eaters.

By far the best snail predator out there is the dwarf puffer fish. Dwarf puffer fish will decimate a snail population in a matter of days, and are capable of crushing snail shells with their beaks. Even the tough Malaysian trumpet snails aren’t safe from dwarf puffers, and while they can’t crack their shells, they will often quickly learn how to hunt them.

While other puffer fish will also work, most of the other commonly available puffer fish are brackish so they can’t be added to a freshwater aquarium.

Another family of fish that enjoys eating snails is the loach family. Probably the two most capable snail hunters of this family are the yoyo loach and the clown loach – both of which are a social fish, and should never be added individually to control a snail problem.

Betta fish are another notable fish that will hunt snail, though they do poorly with most tank-mates. Also, their snail eating abilities are nowhere near the previously mentioned fish.

Assassin Snails

Assassin snails are a relative new comer to the freshwater aquarium trade, and they are rapidly gaining in popularity. Not only are they are an attractive snail in their own right, but few things are as effective at controlling a snail population as these snails.

In my own personal experience, just a handful of these snails were able to clear out a heavily populated 45 gallon (170 litre) tank in a matter of weeks. In fact they were too effective, and they had to be removed before I could reintroduce a small population of Malaysian trumpet snails again (I hadn’t expected them to be so capable of hunting Malaysian trumpet snails).

While you may be worried that you’re trading one snail problem for another with assassin snails, they reproduce sexually, and very slowly. So if only one snail is introduced to an aquarium, then there is no concern that it will reproduce.

However, if you introduce further snails, then they may begin to reproduce slowly – assuming that there is both a male and female present. They lay their eggs individually, and usually only around a dozen or so in all (though there is some disagreement about this number).

Controlling Snails

Depending on whether your goal is snail eradication or just control, then these methods can be used individually or in conjunction with one another. I often recommend that beneficial snails like Malaysian trumpet snails and ramshorns snails be left alone in the home aquarium, but it comes down to each individual’s preference.