How to Control Pest Snails in a Fish Tank
Snail Infestation in Your Aquarium
You’ve worked hard on your new aquarium. You’ve stocked it appropriately, and your fish appear happy and healthy. Maybe you’ve even included a few live plants, and the whole thing is looking pretty darned good if you say so yourself.
But, as you sit back and admire your work, you notice something strange. There’s a critter in there you sure don’t remember inviting, and when you look closer you realize he's brought a few friends. What the blazes is going on here?
Those tiny snails that mysteriously appeared in your tank are considered pests by many aquarium owners. They multiply like crazy, and unfortunately, they are a challenge to get rid of. Usually, they or their eggs come in on live plants or on bits of gravel from a fish store, and they are hard to spot.
Because of this some aquarists quarantine their plants and dip them in a bleach solution before planting. You can also make sure you don’t add any excess water or material from bags when you add new fish to your tank.
Still, no matter what precautions you take you may find your tank infested. This article discusses a few natural ways to control and possibly eliminate snails in your fish tank. While there are over-the-counter chemicals available that are intended to kill off invertebrates, I’ve always tried to keep things as natural as possible.
Let’s get to it. Those snails aren’t going to leave on their own.
Types of Pest Snails in an Aquarium
The typical types of pest snails are:
Tadpole or Pond Snails
These are the most common snails you’ll encounter, and they breed like crazy. They have small, rounded shells and grow to about the size of a pea. They lay eggs in gelatinous globs on surfaces such as plants, decorations, and even the tank glass, and that’s one of the reasons they are so invasive.
They have taller shells with a spiral shape and they grow to around the size of a dime. They too lay their eggs in clutches along aquarium surfaces. Since they don’t breed as rapidly and are somewhat attractive you may not mind having these guys around.
They have elongated, cone-like spiral shells and grow to about an inch in length. Even if you have them they may be tough to spot when tank lights are on, as they tend to burrow into the gravel and come out in the dark. Like pond snails, they are prolific breeders, but they are live-bearers who don’t lay eggs.
Be aware that we aren’t talking about Apple Snails, Mystery Snails or other aquarium pets. Those are snails you intentionally add to your tank, and if you have them you need to consider them in your approach to dealing with pest snails. In other words, don’t harm your pets in an effort to get rid of the pests.
Are Snails Good For a Fish Tank?
Believe it or not, those little snails actually do some good in your tank. They work as scavengers, cleaning up waste, debris, and uneaten food. They also eat algae to some extent. If you only have a few, and you don’t mind the look of them, you may not consider them pests at all.
The problems start when their population gets out of control. Snails breathe, create waste and decompose when they die just like any other fish or animal in your tank. They add to the bioload, meaning your aquarium not only needs to support your fish but an ever-increasing population of snails as well. They are so tiny that a few of them surely won’t matter, but if you let things get out of control before long you’ll find that the tank, and the fish, are under constant stress.
Personally, I also believe that all living things deserve respect and humane treatment. That includes critters we consider pests. For this reason, I highly suggest working hard to keep your snail population under control to begin with. When they are allowed to breed excessively many snails must be removed from the tank and destroyed. While this action is necessary to preserve the health of the fish, it never feels good.
I’ll step off the soapbox now. Let’s solve your snail problem.
Controlling the Snail Population
If you’ve already got snails they aren’t going to go quietly. You’re going to have to get your hands dirty. It is a constant effort to physically remove the snails as best you can. You can set snail traps to encourage them to congregate in one spot. There are over-the-counter traps available, or you can build one yourself.
While you’re plucking the little invaders out you can begin to address the things that caused your snail problem to begin with. Like most issues in the aquarium, it basically comes down to poor management practices.
Snail populations explode because of an abundance of food. In some cases, they eat the same things your fish eat. If you are overfeeding your fish, snails will reproduce more quickly, and once this begins there is a sort of cascade effect. If you have a snail problem you may also have an algae problem, as this too is exacerbated by overfeeding and poor tank maintenance.
Smart Aquarium Management Practices
Here are a few things you need to consider if you want to control snails in your fish tank and keep things safe and healthy for your fish:
- Avoid overfeeding: Many fish food containers suggest feeding your fish several times per day. In my opinion, novice aquarium owners do far more damage over-feeding their fish than underfeeding. Once per day is fine, twice at the most, and only as much as they will eat in a few minutes. Remember that uneaten food sits on the bottom or in the filter and rots, but your snails will happily munch it up. By reducing feedings the snails won’t be able to out-compete your fish for the available food, and they will not be able to rapidly multiply. The better you can manage this the healthier your tank will be.
- Algae control: You’re going to have algae in your tank. A little is actually a good thing. But too much of it can make a mess of your aquarium and even harm your fish. It also provides a food source that enables your snails to thrive. To reduce algae you have to physically scrape it from the glass, manage light in your tank and control overfeeding. You can’t rely on an algae-eating fish; you have to do the work yourself, but it’s not as hard as you might think.
- Regular water changes: Clean water is probably the most important thing for maintaining a healthy aquarium. When chemicals from fish waste, decaying food and rotting plant matter build up in the tank it can be very harmful for the fish. The bioload of your growing snail population will only make this worse. Solve this problem with regularly scheduled water changes. For an aquarium without live plants a 15-20% weekly water change is a good goal. If you have live plants you can reduce this to every-other-week, or even monthly.
- Vacuum up excess debris and waste: There are vacuum/water changer devices on the market that make it super easy to do a water change while cleaning the gravel at the same time. These are essentially siphon tubes with a scoop on one end. I've always used the as it is affordable and comes in a 50-foot length. It works very well. Digging the scoop end into the gravel sucks the dirt and debris into the tube, removing some of the food the snails thrive on as well as smaller snails themselves. With the larger siphons, once you’ve removed the desired amount of water, flip a switch and you can begin refilling your tank with the same tube. For more info on this process and to see how I've used my Aqueon device you may want to refer to my Aqueon Water Changer,article on easy water changes.
How To Clean Aquarium Gravel and Other Tips
Aquarium Fish That Eat Snails
There are a few fish that will happily munch up the pest snails in your tank. I've written an in-depth article on fish that eat snails. You may find it useful. I've also included a shortlist below.
If you go this route I highly caution you not to add any fish to your tank that you don’t want in there for the long haul. If you think you can make it work, here are a few to consider:
- Green Spotted Puffer: Puffers will mow through your snail population, but they are not suitable community fish. They also have some challenging care requirements, and must live in brackish water once they are past the juvenile stage. They’re probably not the best choice, unless you are converting your aquarium to a puffer-only tank.
- Clown and Yoyo Loach: These guys will eat snails, but be aware that they can grow somewhat large. If you have a 55-gallon tank or bigger they may be a good choice.
- Betta: Some betta fish may eat smaller snails, but they come with their own set of issues if you wish to keep them in a community setting.
- Goldfish: Many larger Goldfish will hoover up snails in your tank. In fact, a local pet store in my area had a big Goldfish they would move around to the different tanks to keep the pest snails under control. If you consider trying this approach be aware that Goldfish are not suitable for tropical aquariums in the long term. He will have to live in his own tank, and only come out a few hours per week for snail duty. I do not suggest trying this approach with a Betta, in case you are wondering!
- Assassin Snail: Your best bet may not be a fish at all, but another invertebrate. Assassin snails hunt down and eat other snails. They'll also consume leftover food and even algae. A few in your tank will have your pond snails shaking in their shells.
- Cories and other scavengers: Cories are a nice fish to have in your tank even if you don’t have snails. While they won’t eat the snails themselves, they may eat the eggs. But be aware that they can only do so much, and they can’t eat eggs in crevices where they can’t reach.
- Gourami: You may or may not have luck with gourami. Some aquarium owners swear they will eat snails, while others dispute this. I have often kept gourami before and never noticed them eating snails, but if you wish to have them in your tank anyway you might have some success.
Advice for Aquarists with Strong Stomachs
I’ll warn you now: What you are about to read is a little rough. If you are the squeamish type or some kind of radical animal activist, you’ll want to skip ahead to the next section. The information I'm about to present will only make you mad at me and possibly the world as a whole. You have been officially warned.
If you are forced to remove snails from your tank they must be destroyed. Unless you have a puffer to feed or want to keep a dedicated snail tank there are few other options. But there is one if you have the stomach for it.
Most fish will eat snails. The problem is, except for a few mentioned above, they can’t manage the shells. But, if you help out a little by removing the snail from the shell, your fish ought to gobble it up. You do this by crushing the shell with your fingers or some other device. Some aquarists use a pluck-and-squish method, where they grab snails directly off the glass with their (clean) hands, crush them with their fingers and drop them right back in the tank.
This may sound like it contradicts my earlier statements about treating animals humanely even if they are pests, but I don’t think so. Realize that most of the things you feed your fish come from another animal source anyway. And, if you intend to discard and destroy the snails it is far better for them to have a quick demise rather than a long, drawn-out death. At least this way they are being put a use, to feed other living beings.
Think of it like raising and eating your own cows or pigs for meat rather than buying beef or pork from a store. In the same way, this approach may not be for everyone, but I always felt better thinking the snails were at least part of the food chain rather than just tossed aside.
Of course, if you keep your population under control you won’t have to worry about discarding snails to begin with, and that’s always the best approach.
Learn to Love Snails
If you have rats in your house you’re understandably going to go to any means necessary to get rid of them. They spread disease, ruin food, destroy wiring and other parts of your home and cause a whole host of additional nasty problems. Even if you only have a few they have got to go.
Aquarium snails aren’t really the same kind of pest. They can be beneficial in small numbers, and help to keep your tank clean and tidy. If you can manage to keep them under control you may just consider them another inhabitant of your fish tank.
They can also be fun, sometimes anyway. I once had a single ramshorn snail in a 55-gallon tank, who presumably hitchhiked in on a plant. Every day I would look to see where he was and what he was up to. Sometimes he would float around the tank, drifting with the current. I was bummed when he died.
But, if pest snails get out of control in your fish tank you have to take action. I hope I’ve helped you learn a thing or two about how to manage them. If you have any questions feel free to ask in the comments section and I’ll do my best to help.
Fish Tank Overrun with Snails?
How bad is your pest snail problem in your aquarium?
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.