How To Tell If Your Aquarium Snail Is Dead Or Sleeping

by Aquarium Scoop | Last Updated: January 6, 2023

Is your snail dead or just sleeping? There are a few signs to look out for if you suspect your snail is dead.

In this guide you’ll learn:

  • How can you tell if your snail is dead or just sleeping?
  • How long do snails live?
  • Why do snails die?
  • How to keep snails healthy
Featured image showing a common aquarium snail

Aquarium snails can sometimes be considered pests but these beautiful creatures can serve a lot of purpose in freshwater aquariums. They can help keep your tank clean by keeping algae and detritus in check. Some types of snails can even help aerate your gravel or substrate as they burrow into it. They sometimes fall into some level of inactivity similar to a state of hibernation and look dead. However, they may just be sleeping or resting. Discover how to tell if your aquarium snail is dead in the article below. There are also tips on how to keep them healthy.

How Can I Tell If My Aquarium Snail Is Dead?

If your snail is putting off a foul odor, is unresponsive to being picked up, or is not retracting into its shell if you poke it, these are clear indicators that your snail is likely dead and not just sleeping.

If you suspect that your snail may be dead, it’s best to take it out quickly and place it in a separate container to perform the checks listed below. This is to prevent further fouling of your water if it is dead. Ammonia given off by dead snails can affect the other snails and inhabitants of your fish tank, which can often lead to a stinky fish tank.

Is Your Snail Just Sleeping?

If your snail is not giving off a bad odor, chances are they are just sleeping or even hibernating. Snails can sleep for periods up to 15 hours, so don’t just flush them if they haven’t moved in a while.

Evidence Of A Dead Snail

Foul odor

A dead snail will give off a foul odor, so the best way to tell if your snail is dead is to give it a sniff test. As a snail dies, they decay and decompose quickly. They cause a spike of ammonia levels in your water and will give off a foul odor when you pick them up. The smell is often a foolproof sign that your snail is, unfortunately, dead.

Physical signs of death

A dead snail will be unresponsive even after picking it up or gentle prodding or tapping on its shell. Snails also shrink and lose mass and may even fall out of its shell upon death. The snails’ shell can also turn brittle and develop a dull coloration as the snail inside starts to decompose.

Watch for retraction

If the snail’s body is out of its shell, you can try to gently tap its shell. If it reacts and retracts back into its shell then it is definitely alive. You can also try to gently prod its belly to see if it reacts. If it doesn’t then it may have passed. The body of the snail can even fall out of the shell as you move or pick it up. However, some snails may be braver than others and won’t retract. Try other ways to tell if it is dead such as the smell test.

You can also lightly tug on a snail’s trapdoor or operculum and see if it reacts by tugging back. A dead snail will not tug back; it will also have an open trapdoor.

Place the snail in a separate container

If you’re still unsure, place your snail in a separate container or bowl with water. This may stimulate a response as snails can be curious about their new surroundings. If not, perform another smell test to make sure. 

You may also want to observe your particular snail at night as these creatures are nocturnal.

Check your water quality

Regular monitoring of water quality is one of the best practices you can do as an aquarium keeper. If you notice a spike or an increase in ammonia levels, check for any inactive snails and make sure they haven’t died and started to decompose causing an increase in ammonia levels.

📚 Read More >> How To Get Crystal Clear Aquarium Water

Expert Tip

Be careful when handling a dead snail as you take it out of your tank since the remains can disintegrate and foul your water really quick. The smell can also take a while to clear out if it gets onto your hands or clothes.

What Is The Lifespan Of An Aquarium Snail?

Aquarium snails do have a certain lifespan so your pet may have just died due to natural causes. Here’s a list of common freshwater snails and their lifespans so you can check.

SnailApproximate lifespan (years)
Apple snails1 to 3 years
Assassin snails (Helena) 2 years
Elephant or Rabbit snails1 to 3 years
Malaysian Trumpet snail1 year
Mystery snails1 year
Nerite snails1 year
Pond snails1 year
Ramshorn snails1 year

Why Do Snails Die?

Unfavorable living conditions

Certain snail species require specific tank conditions so make sure you are familiar with your snail’s requirements. For example, make sure your snail is a freshwater snail. Though some marine snails such as the nerite snail can adapt to brackish and freshwater conditions, they can sometimes die off due to stress and inability to adapt.

Snails are nocturnal creatures so excess sunlight may be detrimental to them. They can stop eating and grow weak if they are exposed to too much sun. Avoid this by setting up hiding places in your tank using rocks, faux caves, or plants. Make sure your tank isn’t getting full sunlight and is partially in the shade. 

Poor water quality

As with all your tank inhabitants, your snails will be susceptible to fluctuations in certain parameters such as temperature, pH, and hardness of your aquarium water.

Snails are also sensitive to the cleanliness of the water so toxin build up from waste should be kept at very low, almost 0 ppm levels. An aquarium testing kit is a good way to monitor ammonia, nitrate, and nitrite levels in your water which are toxic to your snails at higher concentrations. Water with poor water quality can lead to poor health in snails and fishes.

Some snails breathe in dissolved oxygen in the water through gills instead of lungs (nerite and mud snails). Lack of dissolved oxygen in the water can affect these snails (as well as other inhabitants in your tank). If you see snails moving up to the waterline, they may be “gasping” for air. Dissolved oxygen can be quickly used up if you have an overstocked tank, waste build-up, biofouling, high temperatures, and overall poor water quality.


Copper in certain plant fertilizers and tank and fish medications and treatments is fatal to snails so make sure to check the ingredients of any conditioners you add into your tank to make sure they are safe for use in tanks with snails.

Aggressive tankmates

Other snails or fishes in your tank can turn aggressive towards each other. Make sure everyone in your aquarium can live together in peace. Certain fishes such as: gourami, cory catfish, betta, and clown loach may take a snipe at your snails trying to eat them. Make sure these fishes are well fed so they don’t make your snails their next meal. Bigger snails may also attack smaller ones.


Parasitic, bacterial, and fungal infections as well as other diseases are easily transmittable between snails so if you notice one looking off or looking inactive, it’s best to isolate it to make sure the others are not affected. 

Food issues

Snails can lose their appetites if they get too hungry making it harder to get them to eat again. This may lead them to develop an illness. Make sure your snails are well fed to avoid this.

Contamination from pesticides in certain fruits and vegetables, even in small amounts, can also harm your snails. Make sure to source your snail food well and wash them thoroughly before feeding to your snail. 


Snails can be curious and cover a lot of ground while searching for food or prey. They often end up climbing the walls of your aquarium or some of the rocks and decorations you have. When they fall and end up upside down, their soft underside may become susceptible to aggressive tank mates. They cannot easily make themselves upright so if they get stuck in this position for an extended period, they can become prey, too stressed out, hungry, and eventually die. 

Sometimes snails (especially large ones such as Astraea and Cowrie snails) can fall from the aquarium glass and hit their shells on the substrate causing an injury that may lead to their death.

It’s also possible for your snail to get stuck in your filter and become injured. Prevent this by using a filter cover to keep your snails safe.

How To Keep Snails Healthy

Diligent and proper aquarium keeping is key to the good health of your tank’s inhabitants. This includes proper monitoring of water quality, making sure your filter works, and keeping your tank clean.

Supplement calcium for shell building

Snails will need to absorb calcium in the water for shell building. If you keep a lot of snails in your tank, there may not be enough calcium in the water or it may have been depleted due to shell building. To counter this, supplement calcium levels in your water by placing a cuttlebone in your tank. Cuttlebone is available in most pet stores. Boil your cuttlebone briefly in water to clean it and make sure it doesn’t float 

You can also make use of tropical or goldfish vacation feeder blocks which have food covered in calcium that dissolves in your tank over time. 

Provide a varied diet

Though most snails are algae consumers, some actually need a more complex diet to thrive. Mystery snails, for example, do not care much for algae and should be fed with vegetables such as lettuce or blanched cucumber. Other greens rich in calcium (kale, spinach) work well to keep them from going hungry.

Provide optimum living conditions

Again, it goes without saying that your aquarium should be well kept to ensure the good health of all its inhabitants, including snails. This means you should have good water quality and excellent filtration. The levels of ammonia and other toxins should be kept in check as well as other water parameters such as temperature and pH. Vacuuming out uneaten food soon after feeding time is a good way to keep your tank cleaner for longer periods of time.


What to do with a dead snail?

You should immediately take out a dead snail from your tank and dispose of it properly to prevent your tank water from fouling. The spike in ammonia that comes from a decomposing snail can affect your fish and other snails.

It’s best to place it in an airtight bin or a resealable bag and keep it in the freezer until garbage day to keep the stench from getting worse. You can also opt to place it in with a compost pile covered with lots of dirt.

If you have enough scavengers in your tank (e.g. at least 15 hermit crabs), you can leave it in for your scavengers to devour. However, if it’s a particularly large snail, you may want to take it out to prevent it from increasing ammonia levels in your water. 

You can also opt to clean the shell out once your scavengers are done with it and place it back in your tank for decoration or perhaps for a hermit crab to make into their new home. You can also recycle the shell by placing the dead snail in a bag with water for a month to let the remains decompose. Clean the shell thoroughly after then place it back in your tank.

In any case, it’s best practice to check your water quality after you take out a dead snail and watch for any spikes in ammonia or other parameters. It’s best to perform a partial water change to be sure by replacing 30-50% of the water.

Do snails float when they die?

Not all floating snails are dead – they may simply be hungry or trying to hitch a ride on the currents. Snails in the wild float to the surface to try and consume more food. They also do this to take advantage of surface currents so they can travel faster to other areas, perhaps in search of food or prey. 

When snails die, they can float as they lose mass upon decomposing. This can cause a snails’ shell to become more buoyant and float. If you see one floating, it’s good to do a smell test to check if it’s dead.

Expert Tip 🧠

The most common causes of browning plants are pests, diseases, and nutrient deficiencies.

Is my snail dead or hibernating?

Snails can sleep for long periods of time. They can be inactive from 2-3 hours or even up to 13 hours at a time. If your snail is starting to smell, feels lighter, and is not sticking to the walls of your aquarium then it may be dead. 

If you notice that your snail is immobile after a large meal then it may just be resting. However, if you notice something off in your water quality then your snail may be inactive or sleeping due to stress from changes in your water quality. 

How do I know if my snail is alive?

Do a smell test. Dead snails will give off a foul odor from their shells. They quickly decompose so they start giving off a smell even if they’ve been dead only for a while. 

If they’re still stuck to the walls or rocks of your tank or it’s after a big meal then your snail may just be sleeping. Dead snails will not be able to stick to any surfaces. Snails are very inactive as they sleep or hibernate. They can sleep from 2-3 hours, 13 hours at a time (in 7 separate bouts), or even up to days at a time.

They will also slightly react from being taken out of the water or gently prodded. You can tap its shell a bit and see if it retreats back. Snails also tend to be curious of new surroundings so placing them in a smaller container with water can coax them into activity.

How long do aquarium snails live?

Most aquarium snails live up to a year with some species living up to 2 or 3 years (apple, assassin, and elephant snails). Make sure you provide the right care for your snails so they reach their full lifespan. Snails will thrive with the proper tank conditions and adequate food supply.


Snails have the tendency to be inactive or sleep/hibernate after a good meal making it look dead. There are several ways to check if your snail has passed, one of which is the smell test. Decaying snails will give off a very foul odor. It’s good to be able to check if your snail is dead quickly as it can severely affect your tank’s water quality.

Further reading

Useful articles for information on snails
Freshwater snail
Operculum (gastropod)

Snail care sheets (PDF)
Freshwater Snails
Aquatic Snails

Interesting article about snail behavior
Behavioural evidence for a sleep-like quiescent state in a pulmonate mollusc, Lymnaea stagnalis (Linnaeus)

FAQs on Freshwater Aquarium Snail Behavior