Nerite Snails Crawling Out of the Tank: Reasons & Solutions

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I can’t count how many times I caught my nerite snails climbing out of the tank. In the beginning, I thought that this is just how they behave. However, over the years, I learned that adjusting their aquarium has a lot to do with that. To solve the issue in your tank, I decided to share all the possible reasons and solutions for the escaping nerite snails issue.

Nerite snails tend to crawl out of the tank when stressed, typically secondary to inappropriate ammonia, nitrates, nitrites, and pH levels. However, that also happens in tanks with aggressive tank mates or when the substrate is too sharp. To avoid injuries, the snails will get out of the water.

As we move forward, I will show you how to solve the escaping nerite snails situation in your tank. I will also explain how to adjust the water and improve your tank’s substrate to make it more suitable for snails.

Why do my Nerite Snails Keep Trying to Escape?

Nerite snails are a convenient addition to most aquariums. They are hardy creatures that can adapt to a variety of aquarium conditions. As a result, they are relatively easy to maintain. If that wasn’t enough, they are proficient algae eaters that aquarists use to keep their tanks clean.

You would be hard-pressed to find a superior species of snail for your fish tank. That being said, these creatures have one major fault. Nerite snails are renowned escape artists that will take any opportunity you offer them to crawl out of the water.

However, that doesn’t always happen. Some aquarists will tell you that their snails never leave the tank. But such situations are rare. In most cases, any nerite snail you add to your aquarium will eventually attempt to crawl out of it.

The reasons that encourage such behavior tend to vary. They include:

1. Poor Tank Conditions

Like most creatures, nerite snails require specific parameters to thrive in a tank. As was noted before, they are quite hardy, but that isn’t an excuse to keep them in a hostile environment. Like fish, they will eventually rush to the surface to escape low quality water.

However, unlike fish, if the situation below doesn’t improve, they can simply crawl out of the tank. That is why you cannot afford to neglect a tank with nerite snails. They deserve just as much care as your fish.

Some factors that can affect the conditions in your nerite snail tank include:

Aggressive Tankmates

Nerite snails are peaceful creatures. They get along with everyone, and you won’t find them antagonizing their tankmates. You can keep them alone or in groups since they won’t make a fuss either way. You need to respond to their peaceful temperament by pairing them with equally peaceful creatures.

Species like Loaches and Macrobrachium Lanchesteri shrimp can make life in the tank unbearable for your nerite snails, forcing them to seek greener pastures outside the tank. Also, if the tank is too crowded, your snails will look for a more suitable environment.

Inappropriate Substrate

Nerite snails do not appreciate rocky substrates. The bottom of a snail’s body is delicate, and a substrate with sharp edges can damage the creature. The same is true for decorations with sharp and rough sections. The harm they suffer from crawling over these objects could encourage the snails to flee the tank.

Poor Water Parameters

Nerite snails are available in various types and species. For that reason, the parameters they require will vary as well. However, they typically expect temperatures ranging from 65 to 85 degrees F and a pH ranging from 7.0 to 8.0.

The nitrates should be less than 20ppm, and the ammonia and nitrite levels at zero. If you usually don’t test your water, I highly suggest starting now. I personally use the API Aquarium Test Kit (link to Amazon). That affordable bundle lasts forever and measures all the necessary toxins within minutes.

Also, the water temperature should be stable. A low-quality heater that causes the water to fluctuate could stress your fish and encourage your nerite snails to escape. After testing numerous heaters, I found the Cobalt Aquatics Neo-Therm Pro Aquarium Heater (link to Amazon) to be the best choice. I also reviewed it here.

It would also be best to pay close attention to the water hardness. The creatures use the calcium in the water to develop and maintain strong and healthy shells. Soft water that is too acidic will harm their shells, causing them to dissolve. The absence of suitable water parameters will compel nerite snails to escape the aquarium.

2. Inadequate Food

As was noted before, nerite snails are algae eaters. They will scrape all the algae off the plants and decorations in your tank. If the algae in their environment aren’t enough to keep them sated, you need to supplement their diet with vegetables and wafers. 

If you cannot feed these creatures to their satisfaction, they will look for food outside the tank. Start with some broccoli and green beans. As the video below emphasizes, calcium supplements could also improve your snail’s shell and general state. I personally use Organic Calcium for Pet Snail (link to Amazon).

3. High Numbers

While nerite snails are peaceful, you cannot afford to keep too many of them in a single tank. First of all, overcrowded tanks will stifle them, preventing the snails from moving as freely as they would like. Secondly, if you have too many snails, they will eat all the algae in the tank, creating a food deficiency that will drive them out of the aquarium.

The nerite snail numbers are not your only concern. The snails will also respond negatively to an abundance of fish and plants. The overcrowding will induce anxiety and stress, which are strong reasons for nerite snails to escape the tank.

4. Natural Behaviour

Make sure your nerite snails have escaped the tank before you panic. The creatures live in intertidal zones in the wild.[1] They are not supposed to spend all their time in the water. The regions they frequent are only submerged underwater for a portion of the day. Eventually, the water recedes, leaving the snails exposed to clear air.

In a tank, nerite snails will replicate this occurrence by leaving the water and resting on the wall’s interior sections, above the waterline.[2] This is why you are encouraged to study your tank carefully before concluding that your snails have escaped.

Look at all the hard surfaces. Some snails will sneak into the filter intakes, remaining hidden for hours or even days at a time. Other snails will attach themselves to hardy plants with leaves above the waterline.

5. Curiosity

Nerite snails are curious. Sometimes, they wander out of an aquarium simply because they want to discover the world waiting outside. This is the primary factor that has earned the snails a reputation as escape artists.

If you look for all the possible reasons that might force your snails to escape and come up with nothing, curiosity is most likely to be the case. Some nerites snails are more curious than others and will explore their environment more frequently. Sometimes, it happens outside of the water.

How to Prevent Nerite Snails from Escaping?

Your snails have a better chance of surviving if they stay in the water. Therefore, you should act immediately to resolve any issues that might encourage them to leave the tank:

1. Improving the Aquarium Conditions

If your snails keep running away because of the poor conditions in their aquatic environment, you can compel them to stay by improving their water quality. That typically involves correcting the pH, ammonia, nitrates, nitrites, and water hardness.

Toxins – If the concentration of substances like ammonia and nitrites has exploded, carry out an immediate water change. You should also remove rotting organic substances and leftovers whose presence contributes to the manifestation of ammonia.

PH and Temperature – As was mentioned earlier, the API Aquarium Test Kit (link to Amazon) can measure nitrates, nitrites, ammonia, and pH. Use it to test the pH. Also, don’t forget to install a heater and a filter. Nerite snails can survive in a wide range of parameters, but they need a higher pH (8.1 to 8.4) and temperature (72 to 78 degrees F) to thrive.[3]

Water Hardness – Nerite snails require hard water that is rich in calcium. The calcium will benefit their shells. You can use crushed coral and limestone to raise the hardness. You can also add calcium supplements to the water, particularly when the snail’s shell has started showing signs of wear.

Tankmates – Avoid large and aggressive species like cichlids. Prioritize smaller tankmates with peaceful temperaments such as tetras and guppies. Nerite snails can also co-exist with shrimp.[4]

Substrate – If you want to protect your snails from the harm caused by gravel and other substrates with sharp edges, cover the bottom of your tank with a sandy substrate.[5] They can crawl over fine-grained sand without being cut or scratched. If you want to use gravel, get the kind that has rounded edges. Decorations are in the same boat. Sand their sharp surfaces down before you add them to the tank.

Marine vs. Freshwater Species – Nerite snails come from brackish waters. They can live in freshwater, but they require some aquarium salt in their tank. That said, some nerite snail species can only thrive in either marine habitats or freshwater aquariums. Hence, I suggest consulting your retailer. They will tell you whether the nerite snails you want to buy are freshwater species or if they should live in marine environments.

2. Avoid Overcrowded Tanks

As was noted before, nerite snails need their freedom. To avoid overcrowding, you need five gallons of water for every nerite snail.[6] That will provide the snails with a relatively peaceful environment. Also, they won’t have to climb out of the water. They will have plenty of places to research inside the tank.

Obviously, it is essential to take their tank mates into that equation. If you grow aggressive fish such as cichlids, perhaps 5 gallons per snail are not enough. The more bullies your tank features, the larger the tank you should acquire.

3. Adjusting Their Food

As was previously mentioned, snails eat algae. If your tank doesn’t have enough algae to satisfy your snails, I highly recommend supplementing their diet with carrots, zucchini, and other blanched vegetables. If necessary, cook their meal beforehand so that it is edible and digestible.

You can also feed them algae wafers. But make sure you remove any wafers that go uneaten (rotten leftovers will quickly release toxins such as ammonia and nitrites). Snails eat all day. The easiest way to keep them happy is to provide a stable food source.

4. Water Line & Lids

First, try not to fill the aquarium to the top. This will only make it easier for your nerite snails to climb out of the tank. Keep the water level a few inches from the top. This way, your snails won’t be forced to climb outside in the search for dry areas.

Lids are probably the most straightforward solution for that issue. Start with placing a cover over your aquarium. The lid should be tight fitting since nerite snails are relatively small. They will use any opening you offer them to escape. Nevertheless, the cover shouldn’t prevent the gaseous exchange from taking place. 

Some aquarists even use VaporRub and vaseline products to make the edge and the walls near the top of the tank so slippery that the snails are incapable of climbing them. But that is probably the solution you should take if nothing else has worked.

How Long Can Nerite Snails Live Without Water?

Nerite snails are supposed to spend a portion of their day out of the water. However, the exact duration they can spend out of the water without dying isn’t clear. Most people agree that they can spend hours outside an aquarium.

However, no one can tell you the exact number of hours. Some people claim that their snails have survived for over 24 hours outside the tank. Others will argue that their snails died within two or three hours of leaving the tank.

A few aquarists have suggested that their snails can survive on dry land for several days at a time. Ultimately, no one knows for sure. What you need to know is this: they won’t die immediately. Therefore, once your nerite snails leave your tank, don’t be so quick to give up on them. If you can find them and return them to the water in time, they will recover.


Nerite snails that escape their aquarium are one of the most prevalent issues aquarists have to face. The best way to deal with it would be testing the water quality. High ammonia and nitrates may stress the snail, forcing it to seek more pleasant areas.

Also, I encourage you to lower the waterline level so it won’t be that easy for the snails to escape. You may also install a lid while making sure that it is tight and secure. Bear in mind that nerite snails can survive a few hours out of the water, so you shouldn’t be nervous when you catch them outside the tank.