Snail Eggs in Your Aquarium: What You REALLY Need to Know

If you are an aquarium or snail owner, you REALLY need to know what to do if you end up with snail eggs. Well, unless you want to be overrun by a little gastropod gang, of course. With many species able to fertilize themselves, it pays to be armed with the right reproduction information; otherwise, keeping on top of your aquarium snail population really will be quite the battle. Especially if you didn’t put the snails in your tank in the first place!

What Do Snail Eggs Look Like?

Some snail eggs are so small you’d easily miss them, only 0.01 inch (0.03 cm) across.

snail eggs on a hand

The small size of many a snail egg is what enables gastropod hitchhikers to make their way into home tanks by accident. They are often not spotted on rocks or plants, etc. When the plants or decorations are put into the tank, the eggs can hatch, incorporating snails into a tank they weren’t previously in. Sometimes, the snail will lay a cluster of clear egg, which are even harder to spot.

Luckily, many snail species lay them in clusters, which can be formed of 100 eggs or more. They’re easily to spot, around 0.25 inch (0.64 cm) across. You are more likely to notice the clusters, which are inside a gelatinous sac.

Depending on the species, there can be different sizes and colors of eggs. Different species also lay different numbers of eggs. Ramshorn snail eggs come in clusters of between 12 and 30. Nerite snails, on the other hand, lay clusters of between 30 and 100 eggs to hatch.

Can Snail Eggs Be Black?

Yes, they can. Mystery snail eggs (a freshwater snail known scientifically as Pomacea bridgesii) are known to turn darker, almost black in color, when they are fully fertilized. You can see a small, dark dot growing in the center.

Can Snail Eggs Be Yellow?

With a clear exterior and a beige-yellow inner growing young snail, assassin snail (Clea helena) eggs can sometimes look yellow.

Nerite snail eggs look like sesame seeds to a lot of people, often with a yellow tinge to them.

Can Snail Eggs Be Pink?

Yes, the freshwater snail eggs belonging to the apple snail can be almost Barbie pink in color! They turn a paler color as they are fertilized.

As well as being yellow and dark, almost black, mystery snails can also have a pink hue to the cluster. The pink is more of a pale, baby pink shade than the bright apple snail egg cluster.

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Snail laying eggs on a stalk

How Do You Know if Freshwater Snail Eggs Are Alive?

If you do not want an infestation of snails in your tank, it is best to assume that all snail eggs are alive.

Many eggs and egg clusters will change color as they are fertilized. Apple snails, for example, have eggs that are bright pink to start with, turning a pale pink when they are fertilized. If they are still bright pink after 2 to 4 weeks, they are not fertilized.

Mystery snails also turn darker in the center when they have been fertilized.

If you get the opportunity to take a closer look at the snail eggs, you will sometimes see details after a few days. Ramshorn snails, for example, will start to develop a bubble-like interior after a week or so. This is a sign that a baby ramshorn snail is developing inside.

Where Will Snails Lay Their Eggs in an Aquarium?

Freshwater snails have a habit of laying eggs in awkward, difficult-to-see places in aquariums and tank environments. Both sea and freshwater snails do this in the wild, too, to keep the eggs safe until they hatch.

If snails were to lay their eggs out in the open, where everyone and every animal could see, they’d soon get eaten and the species would fast become extinct!

Some species of snail on land will bury their eggs in soil or other substrate materials.

Freshwater aquarium and sea snails like to lay their eggs in cracks and crevices of rocks, on the underside of driftwood and other floating objects, or hidden amongst the leaves of live plants. In an aquarium, they can be hidden underneath tank equipment (such as pumps and thermometers, etc.).

Apple snail eggs will not hatch if they are in the water. The female usually lays a string of eggs above the surface of the water. In an aquarium, this can mean on the glass or container sides, on ornaments, on tank equipment, and on live plants.

snail eggs
Snail eggs

Ramshorn snails tend to lay eggs attached to the freshwater aquarium glass, making them easier to see than other species.

Nerite snails will lay eggs pretty much anywhere in an aquarium – glass surface, plants, on decorations, and more. In the ‘wild’, they seem to have a preference for driftwood.

When Do Snails Lay Eggs?

Snail eggs usually lay eggs around 14 days after breeding but this will vary from species to species.

Some freshwater snail species have a faster reproduction cycle than others, and lay more eggs at a time.

Assassin snails, for example, are quite slow breeders and the eggs take a relatively long time to hatch. Not only that, they only lay a few – roughly 4 – eggs at a time.

Ramshorn snails, also freshwater snails, lay their eggs much more frequently, on the other hand. They also lay much larger clusters – up to 100 eggs. It all depends on a lot of things, including water temperature, tank population, whether there is enough algae to feed on, and more.

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When Will Snail Eggs Hatch?

Different snail species have different egg hatching rates, so you will need to know which species you have in your tank.

The eggs of nerite freshwater snails will likely never hatch in an aquarium. This is because the eggs require very specific water conditions – brackish water, which is a combination of salt and fresh water.

If you wanted the freshwater snail eggs to hatch, you would need to move them to another container of slightly warmer brackish water, often referred to as a holding or breeding container.

Mystery snail eggs take approximately three or four weeks to hatch, and the clutches are usually a bit bigger and more obvious than some of the other aquarium snails.

Assassin snail eggs take a much longer time to hatch – up to 8 weeks in some cases.

Do Snails Eat Their Own Eggs?

Yes, it is quite common for snails to eat their own eggs. This happens a lot when there is not enough algae or other food sources.  

You can prevent snails from eating their own eggs in your tank by ensuring they have enough food, such as algae flakes or dried seaweed. It won’t stop the cannibalism entirely, however. It’s just a weird and unpleasant part of nature.

Assassin snails will eat their own eggs, and the eggs of other snails.

snail eggs on sand

Which Fish Eat Snail Eggs?

Snail eggs actually make for great fish food if you have gourami, loaches, koi, whiptails, bettas, guppies, pleco, catfish, goldfish, and more. Unfortunately, some of these fish will also attack and eat adult snails if they get the opportunity.

Fish that eat snail eggs can grow to large sizes. Some aquarium owners also note them being more aggressive after a heavy snail egg feeding frenzy.

Can Snail Eggs Hatch Underwater?

Yes, some snail eggs to hatch underwater, but not all.

Clea helena eggs will actually die/not hatch if they are laid by the snail underwater.

Why Are Snail Eggs Bad in an Aquarium?

Snail eggs aren’t always bad. They are only bad if the population of snails and other tank mates aren’t kept in check.

Overpopulation is bad for any ecosystem, even an artificially created one. If you have too many snails, even baby snails, in one tank, they will compete for food and other resources. It will inevitably lead to masses of snails dying, which then upsets the delicate chemical balance of the water if you don’t remove the carcasses quickly enough.

Why Are Snail Eggs Bad for the Environment?

Not all snail eggs are bad for the environment.

Giant African land snails are bad for the environment in many places around the world, including the US and the UK. They are non-native to those places. The introduction of the gastropod to wild Florida and other places has meant they have become a pest species that is upsetting the existing ecosystem and food chain.

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Native snails can’t get enough food because the Giant African land snail is stealing it all, which means that local populations of other snails are being threatened with extinction.

In short: don’t let those snail eggs loose in the wild!

What to Do About Snail Eggs in your Fish Tank

There are a few things you can do to prevent snail eggs from hatching in the tank. That’s assuming you don’t want them to, of course; you could always just leave them where they are and have a tank full of snails.

Turning down the temperature a little bit can affect eggs and stop them from being able to develop. When the water is too cold, they can’t hatch. You will need to find the right temperature so that the adult snails don’t suffer, however.

Turning up the acidity of the water will work in the same way as turning down the temperature, but again, you must ensure you don’t make too many changes that it ends up effecting all living beings in the tank.

Alternatively, you could kill the eggs.

What Kills Snail Eggs?

You can use a number of approaches to essentially kill the snail eggs so they do not hatch.

1: Allow predatory fish or snails to eat them. Clea helena are pretty good at devouring snail eggs.

2: Wearing gloves, scrape out the eggs with your hands and then dispose of them responsibly. It is best to do this when you clean the tank. Some people recommend boiling the eggs to kill them, others suggest putting them in the freezer, or storing them in very cold water.

3: Plow the tank substrate. In doing so, you will disrupt the clutches of eggs that are hidden under there, damaging them in the process. This can prevent them from hatching.

4: Add copper sulfate to the water. Gastropods are incredibly sensitive to changes to the different compounds in water, this will kill adult snails as well as their eggs. Unfortunately, it will also kill other tank mates, such as crayfish, crabs, and shrimp.

Why is My Mystery Snail Laying Eggs Without a Mate?

Mystery snails can’t reproduce asexually, but they can keep hold of fertilized eggs for a long period of time. It could be the case that the mystery snail you added to your tank was carrying fertilized eggs from a previous mating session, if you start to see baby snails.