Maybe you’ve seen large, colorful snails in your local fish store and thought about adding them to your fish tank. Or maybe you’ve had the misfortune of seeing your tank get overrun by snails almost overnight and wondered how they even got into your aquarium in the first place! Aquarium snails can be great in an aquarium, but you need to be aware of how they reproduce and how quickly they can multiply before you decide to add them.
How fast do aquarium snails reproduce? Depending on the species, a snail could lay as few as five eggs at a time, or up to 600 eggs at one time! Typically, it will take one to two weeks for eggs to hatch but could take as long as five weeks. This will vary between species, so some of the snails in your tank, like Ramshorn snails, will only lay about ten eggs at a time. Others, like Mystery snails, can lay 600 eggs at one time.
How fast snails reproduce depends on several factors, including:
- The type of snail
- The way aquarium snails reproduce
- The fish you already have in your tank
I take a look at those factors and more in this article, including how to control the aquarium snail population in your tank in case you get overrun, or to prevent them from taking over in the first place.
Types of Aquarium Snails
There are many types of snails available at local fish stores and from online retailers. Some of these snails are more welcome in an aquarium than others because of how quickly they reproduce.
Briefly, the most widely available aquarium snails are:
- Assassin snails
- Mystery snails
- Malaysian Trumpet snails
- Nerite snails
- Ramshorn snails
- Pond snails/bladder snails
- Rabbit snails
These snails range from a half-inch to 2 ½ inches in length and can come in several unique colors, besides just black or brown.
Of these, pond/bladder snails, ramshorn snails, and Malaysian trumpet snails are often considered pest snails, but any snail in your tank can become a pest species if allowed to breed without any restrictions.
The different types of aquarium snails even reproduce differently, which I look at in more detail below.
How Aquarium Snails Reproduce
Almost all commonly available aquarium snails lay eggs—but how they do this, and how many eggs they lay at one time, varies with the type of snail.
Snails can either reproduce sexually (which takes two snails), or asexually (which only takes one snail).
Snails that reproduce asexually have both male and female sex organs, so a single snail can not only lay eggs but also fertilize them.
Snails that reproduce sexually require both a male and a female snail—the female snail lays eggs and the male fertilizes them. Unfertilized eggs won’t hatch, and you won’t get any more snails. This means that if you only have one of these types of snail, it can’t reproduce in your tank.
Pond snails, which are the type people usually think of when it comes to “pest” snails, can lay 100 eggs at a time per snail! It only takes pond snail eggs 10-20 days to hatch out. So, after two weeks, you could have over 100 new snails in your tank! No wonder they can take over a tank so quickly.
Snails that can reproduce asexually (only one snail needed):
- Pond/bladder snails
- Malaysian trumpet snails
- Ramshorn snails
Snails that can only reproduce with two snails:
- Mystery snails
- Nerite snails
- Assassin snails
- Rabbit snails
How Did These Snails Show Up in My Tank?
Unwanted aquarium snails (meaning: you didn’t plan on adding them to your tank) often hitch a ride on live aquarium plants or sometimes end up in the bag with your newly purchased fish if the local fish store employee isn’t careful what they’re scooping up.
Snails can be tiny, and sometimes it’s not the snail, but their teeny tiny eggs that are on live plants or in hiding in water bags with your fish.
Why Would You Want Any Aquarium Snails?
Often, snails are used to clean up aquarium algae or siphon up leftover fish food and waste. If you’re interested in using snails in this way, then they would most likely take the place of fish like Corydoras, Chinese algae eaters, plecos, Oto cats, etc., which would normally have a similar function.
They can even be good indicators of water quality since some types of snails will attempt to crawl out of the tank when the water quality is bad.
They can be quite entertaining to watch, too, depending on the type.
If you’d like to get a snail (or two!), 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, most peaceful community fish should be fine.
How to Control Aquarium Snails:
Choosing the wrong type of snail for your aquarium can turn into a disaster pretty quickly since several types (as already mentioned above) can reproduce even without other snails.
Before you know it, you’ve got snail eggs everywhere, sticking to the sides of the tank, plants, decorations, or even the gravel. You’ve scooped out everything you can find, but there are still tons of snails everywhere.
What can you do?
Thankfully, you’ve got several options!
1. Handling it the Old-Fashioned Way
If you don’t have too many snails, you can scoop them out of the tank and dispose of them or give them away. The same is true for any eggs you see in the tank.
2. Clown or Yoyo Loaches
If your tank is overrun with snails, and you have the available tank space, a clown loach or a yoyo loach each do an excellent job of hunting down snails, and they’ll even dig under the substrate to root out snails that bury themselves in the gravel!
They actually suck the snails from their shells, so the only downside is having to scoop out all the empty snail shells after your loach is done feasting. (And make sure you have a large enough tank to house the loach, or rehoming it if it gets too big for the tank.)
3. Assassin Snails
As you might have guessed from their name, assassin snails hunt down other snail species and eat them! This can be great for smaller tanks, especially if you don’t have the space to add a 6-12 inch loach.
The only downside with assassin snails is that, if you’re not careful, you could be overrun with them before too long, too, and then you’ll need to find another way to keep down your tank’s snail population.
4. Gourami
Many gouramis love snacking on snails and their eggs.
The only downside here is they’re not very good at finding snails under the gravel, tending to only eat the snails they can see. So, gouramis won’t be able to get everything out of the tank for you, but they can help.
5. Bettas
If you already have a betta, and you see snails in your tank, then you probably won’t need to do anything else, since bettas enjoy eating snails and their eggs just as much as anything else they eat.
Bettas have the same downside when it comes to eating snails that gouramis do, though—they’re not very good at finding snails under the gravel, which is fine if you don’t already have a ton of snails in the tank.
6. Copper Solutions
Copper-based aquarium treatments will also kill freshwater aquarium snails. Two of the most popular treatments readily available in fish stores include Coppersafe by Mardel and Cupramine by Seachem.
The caution here is that copper levels need to be monitored the entire time the tank is being treated to avoid harming your fish, and copper treatments should never be used in a tank with shrimp or other invertebrates. I don’t recommend this for beginners!
In addition, while copper will the snails unless you remove them yourself, they’ll rot in the tank, bringing down your water quality.
7. Cut Down on the Fish Food
A snail’s gotta eat, too, and the less extra food in your tank, the less food that will be available to them.
Pre-treating Plants/Decorations
One way to keep snails from sneaking into your tank on live plants is to treat plants in a potassium permanganate solution before adding them to the tank. This should kill any snails or eggs that may be on the plants.
Be sure to rinse the plants thoroughly after treating them, and then they’ll be ready to enter the tank.
You can also do this to any decorations that were in someone else’s tank or in a tank at your local fish store.
In Summary
Aquarium snails can multiply quickly, and some types only need one snail to reproduce. Many types can even lay several hundred eggs at one time!
If you’d like to add snails to your tank, there are many great options, including mystery snails!
If you ended up with snails on accident, there are several ways to get rid of them, including adding snail-eating fish, getting assassin snails, removing them by hand, using chemical treatments, and reducing how much food you feed your fish.
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