You’ve probably heard horror stories about aquarium snails taking over a tank and negatively affecting water quality, and had second thoughts (or completely changed your mind) about adding aquarium snails to your fish tank. There are lots of snails for sale at local fish stores, though!
Are aquarium snails dangerous in an aquarium? Normally, they’re only dangerous if they’re allowed to multiply unchecked. Too many snails in a tank can harm water quality, reduce the available food supply for the fish in your tank, and/or cause damage to living plants.
Whether snails are dangerous depends on several factors, including:
- The type of snail
- The way aquarium snails reproduce
- How many snails are in your tank
I take a look at those factors and more in this article, including the benefits and dangers of keeping aquarium snails in your aquarium and what to do if you end up with too many snails.
Types of Aquarium Snails
There are many types of snails available at local fish stores and from online retailers.
Typically, fishkeepers tend to gravitate toward Mystery snails, Nerite snails, or Rabbit snails because they’re interactive, have colorful bodies and/or interesting shell patterns, and rarely, if ever, take over an aquarium.
Most often, Pond snails (bladder snails), Malaysian Trumpet Snails, and Ramshorn snails are viewed as pest snails because of how they reproduce.
Snails can either reproduce sexually (which takes two snails), or asexually (which only takes one snail).
Snails that reproduce sexually require both a male and female snail. This means that if you only have one snail, it can’t reproduce in your tank.
Of course, the “pest” snails are the ones that can reproduce asexually (only one snail is needed):
- Pond/bladder snails
- Malaysian trumpet snails
- Ramshorn snails
This makes sense since it’s much harder to control how many snails are in your tank when it only takes one snail to produce lots of hatchable eggs.
However, remember that any snail could become a nuisance in your tank if there are too many snails for the aquarium.
How Did I Even Get Snails?
Unwanted aquarium snails often hitch a ride on live aquarium plants or sometimes end up in the bag with your newly purchased fish.
Most of the unwanted hitchhikers are (you guessed it!) pond/bladder snails, ramshorn snails, or Malaysian trumpet snails, and they can be very hard to spot.
What Are the Benefits of Aquarium Snails?
Why would someone even get aquarium snails, anyway? Often, snails are used to clean up aquarium algae or siphon up leftover fish food and waste.
Many varieties, including Nerite, Ramshorn, and Mystery snails love to munch on algae. In that case, you’d get a snail (or a few) instead of algae-eating fish like Siamese algae eaters, plecos, or Oto cats.
Note that Malaysian trumpet snails will also eat algae, but they can burrow under the substrate (just like pond snails) and can be incredibly difficult to get rid of.
One good thing about the Malaysian trumpets is that burrowing also helps aerate the substrate, so any live plants with roots buried in the substrate will get a little boost from having snails in the tank, too!
Fishkeepers like having snails around because certain species are good indicators of water quality. Believe it or not, some types of snails crawl out of the water when the water quality is bad.
And, contrary to what may come to mind when you hear the word “snail,” there are many colorful varieties available. Mystery snails, for example, can have white, cream, yellow, black, or grayish-blue/purplish bodies, and their shells come in the same color options.
If you’d like to get a snail, make sure the fish in your tank won’t eat or harass them. Avoid gouramis, bettas, and botia-type loaches (clown loach, yoyo loach, etc.) to be on the safe side here. Otherwise, peaceful, community tankmates like tetras, guppies, or even shrimp should be fine.
What’s the Danger in Too Many Snails?
Having too many snails in your tank can cause several problems.
1. Bio-load Overload
Snails, just like fish, have their own bio-load, which means they produce waste in an aquarium, too.
And too much waste leads to ammonia and nitrate build-ups, which can hurt or even kill your fish.
Snails can die unnoticed in your tank, since all you see is the shell, and it’s hard to keep track, if you have a lot of them, of who’s moving and who isn’t. Dead snails also produce ammonia as they decay, which is bad for your water quality and your fish.
In addition, because snails like to travel, the smaller ones are able to fit inside your filter and can block filter openings or damaged impellers.
2. Eaten Plants
Most snails will leave live plants alone, but some absolutely love a plant dinner, like some types of Mystery snails.
Other snails will only munch on plants when they don’t have enough food to eat, and if you have too many snails in the tank, they’re sure to start looking for extra food from your plants. In this case, the snails are only dangerous to your plants, but it’s still something to keep in mind.
3. Not Enough Food for the Fish
Snails have to eat, too–and if there are snails taking over your tank, there’s a good chance they’ve already cleaned up any available algae and most of the leftovers already.
They’ll need to move on to something else to survive, and they’ll happily gobble up all the new fish food you’re adding to the tank once they’ve run through their other food supplies.
If that’s been happening in your tank, your fish aren’t going to get enough to eat for themselves, which means your fish isn’t going to last for too long if the snail population doesn’t decrease, and soon!
Controlling Aquarium Snails
Because several types of aquarium snails can reproduce without other snails, (as already mentioned above) reducing their population to a sustainable level (or eliminating them altogether) can be incredibly hard to do.
By the time you see baby snails in your tank, you’re probably well on your way to an infestation, since many types only come out at night (or when the lights are off) and can happily live under the substrate, only coming out every once in a while to eat.
So while you may only see one or two cute little baby snails, there could be a hundred more hidden around your tank.
Don’t panic–you have several options for controlling the snail population in your tank, though some are more disruptive to your fish than others.
1. Remove Snails by Hand
This works best when you’re sure there are only a few (say less than 50) snails in your tank. Otherwise, the snail population explosion will quickly outpace your ability to remove them yourself.
You can scoop visible snails out of the tank in a fishnet, or smash them against the tank, and then dispose of them.
2. Snail-eating Fish
This may be the best option if you have the extra room in your tank (and compatible fish).
My suggestions are:
- Clown or Yoyo loaches
- Betta fish
- Gouramis (nearly all varieties will eat snails)
If you have a large enough tank, then a clown loach or a yoyo loach would do an excellent job of hunting down snails, and they even dig under the substrate to eat snails that hide in the gravel! They can quickly clear out even the most overrun tanks.
Gouramis or bettas are a better option for smaller tanks since almost every type of gourami loves snacking on snails and their eggs, and bettas also enjoy snail/egg dinners.
Just be aware that gouramis and bettas won’t dig out snails under the gravel. So, they won’t get everything out of the tank for you, but they’ll certainly help!
3. Assassin Snails
Assassin snails are good at hunting down other snails and eating them. This can be great for smaller tanks, especially if you don’t have the space to add a snail-eating fish.
But if you’re not careful, you could end up with too many assassin snails, and you’ll be in the same situation.
4. Copper Solutions
Copper-based aquarium treatments will also kill freshwater aquarium snails, but copper levels need to be monitored while the tank is being treated to avoid hurting your fish. Never use copper in a tank with shrimp or other invertebrates.
You can prevent unwanted snails from getting into your tank in the first place by pre-treating live plants or decorations with a bleach dip solution before adding them to the tank.
Be sure to rinse the plants or decorations thoroughly after treating them, though.
In Summary
Are aquarium snails dangerous? They have lots of beneficial qualities, like eating algae in the tank and cleaning up leftover food and fish waste.
Aquarium snails are only dangerous when there are too many in a tank, which can easily happen if snails are allowed to reproduce unchecked.
Thankfully, there are several ways to get rid of unwanted snails including getting assassin snails, adding snail-eating fish, removing them by hand, and using chemical treatments.
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