Why Is My Mystery Snail Not Moving? Is It Actually Dead?

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Mystery snails are both beautiful and easy to grow, which is why I enjoy having them in my tank. However, sometimes they show signs that worry me.

For instance, quite a few times, I noticed that some of my mystery snails stopped moving. Over the years, I’ve learned how to deal with the issue. Now, I am willing to share my experience.

Mystery snails tend to stop moving when stressed, usually secondary to aggressive tankmates and inappropriate water conditions. However, snails also stay in one spot once they are sleeping, which could be during the day, especially after mealtime.

As we move forward, I will teach you how to deal with a mystery snail that has stopped moving. I will also present a few signs that might indicate that the snail is dying so that you can take the necessary preventive measures.

Why Is My Mystery Snail Not Moving?

If your snail isn’t moving, you shouldn’t be so quick to throw it away. Some people think that an inactive snail is dead. But that isn’t necessarily true. Snails will remain immobile and inactive for several reasons, including:

1. The Snail Is Sleeping

Mystery snails sleep. This might come as a surprise, but it is true. However, while fish and humans typically remain active during the day and sleep at night, snails do not follow any specific pattern. 

They can sleep at any time and in any location. Even more impressive is the fact that snails can sleep for two to three days at a time.[1]

In most cases, snails stop moving once they are sleeping. They will stay in place until they wake up.

Indicators that your mystery snail is sleeping:

  • The snail tends to be still but moves occasionally.
  • The mystery snail will retreat into its shell for protection.
  • The snail’s breathing rate will slow down.
  • Your snail will not respond to stimuli such as changes in light.

2. Your Mystery Snail Hibernates

Snails can hibernate for up to three years. This is unlikely to happen in an aquarium. However, you need to understand that their hibernation can last a long time.

Because hibernation reduces metabolic activity, snails do not eat as much food during this period. They tend to enter this state when the temperature falls.[2]

But again, this isn’t likely to happen in an aquarium. You may see such behavior in the wild, where snails have to contend with winter conditions. In a tank, the temperatures are far too stable.

However, if your mystery snails haven’t moved for days or even weeks, hibernation is a possible cause.

A starving snail is more likely to enter into hibernation. This is because the state reduces metabolic activity, allowing the creature to survive longer on less food.

Therefore, if your snail’s diet is insufficient, you shouldn’t be too surprised if it becomes dormant.

Remember that a hibernating snail shows the same signs as a sleeping snail, but for longer periods (usually several days).

3. The Environment Is Too Hostile

Mystery snails are peaceful creatures that cannot thrive in tanks with aggressive neighbors.

When they encounter aggression, snails will retreat, remaining hidden within their shells. They will remain inactive so long as such threats persist in their vicinity.

In many cases, you will see a cracked shell indicating that your snail has recently been attacked by another tankmate. In other cases, you might find your snail crawling out of its tank or burying itself in the substrate.

4. The Snail Only Goes Active During The Night

Some snails are more active during specific periods than others. It isn’t that uncommon for some mystery snails to become dormant during the day.

They wait until night comes, and the lights go off. And then they come to life, using that opportunity to eat and explore. 

Such snails will trick you into concluding that they rarely move because they are inactive during the day when you are most likely to observe them.

Some snails are the opposite. They become dormant during the night, only coming to life when the sun rises, and the lights come on.

5. The Water Conditions Are Not Suitable For Snails

Snails are sensitive to the conditions in their water. Sudden changes in parameters like temperature and pH can induce stress.

The same is true for extreme temperatures, the wrong pH, and water that is too soft. Stressed snails are less active. Poor conditions compel them to retreat into their shells.

You have to keep an eye on the aquarium’s ammonia and nitrite concentration, not to mention copper levels in the water.

These toxins can eventually kill your snail. But before the snail dies, it will become inactive.

Indicators that the water condition isn’t compatible with mystery snails:

  • Shell problems: Their shell will become thin and brittle. In some cases, it will change its color to black. Other snails may lose their colors.
  • Reduced activity: Your snail will become less active during the day and night.
  • Difficulty breathing: Some snails will exhibit prolonged breathing through their mantle.
  • Lack of appetite: Your mystery snail will be less interested in food.

6. Your Snail Wasn’t Positioned Properly

When you introduce mystery snails to a tank, you have to place them in a right-side-up position.

If you merely throw them into the tank, they are just as likely to land upside-down. A new upside-down snail may try and fail to reach the hard surfaces in the area with its foot.

A snail that cannot reach a hard surface with its foot could fail to turn itself right-side up. A snail that can’t flip over will stay in its upside-down position until it eventually dies.

If your mystery snail hasn’t moved, check its position. If it has been upside down since you added it to the tank, it has failed to flip over.

7. Your Snail Adapts To Its New Aquarium

It is perfectly normal for a snail to become dormant after you add it to a new tank.

It can remain inactive for one, two, or even three days until it becomes comfortable with the tank’s conditions.[3]

This is more likely to happen in situations where the new tank’s conditions vary drastically from the conditions in the old tank.

8. The Snail Has Just Had A Large Meal

Snails can become sluggish or inactive after eating large meals. In many cases, they are merely resting.

This isn’t a cause for concern, since unlike fish, mystery snails rarely get constipated. However, digestion is probably not the case if the snail hasn’t moved for days.

How To Treat Mystery Snails That Stopped Moving?

It is perfectly normal for mystery snails to become inactive on occasion. However, if you think that the dormant state of your snails is abnormal, you can use the following ideas to treat them:

1. Adjust The Water Parameters For Mystery Snails

I highly suggest that you maintain the appropriate parameters in the tank. Mainly, you should adjust the water conditions in a way that will suit mystery snails. That means keeping the following in mind:

  • Temperature – Keep the temperature at 75 to 86 degrees F.[4]

It would be best to use a high-quality heater to prevent unnecessary fluctuations. Even if the average temperature falls within the desired range, fluctuations will stress your entire tank.

  • Water pH – For mystery snails, I recommend keeping the pH between 7.0 and 7.5.

Lower or higher than that will stress the creature and force it to go immobile. I also suggest getting the API Aquarium Test Kit (link to Amazon).

That highly affordable bundle will measure your pH, ammonia, nitrates, and nitrites within a few minutes.

For instance, a three-gallon tank can hold one or two snails. With ten gallons, you can keep a maximum of five snails.

Fifteen gallons can hold no more than nine snails. The more snails you have, the larger the tank.

  • Calcium – It would help if you used seashells, cuttlebone, and the like to enhance the water’s calcium content. This will promote shell growth.

You should also ensure that the water is sufficiently hard. Otherwise, the snail’s shell will suffer.

2. Perform Regular Water Changes

There is no doubt that regular water changes will benefit your snails since they will prevent ammonia levels from spiking.

If your snail is already inactive and you cannot afford to perform a massive water change because of the stress the process may induce, you can add conditioners.

Conditioners can neutralize the toxins in the water. One of the most popular would be the Seachem Prime Conditioner (link to Amazon).

That product will take care of ammonia, nitrites, chlorine, and heavy metals. You should also add a filter. This will keep the water relatively clean.

3. Feed Your Snail Properly

The easiest way to coerce a snail out of its dormant state is to improve the tank’s conditions. But healthy water conditions won’t matter if the mystery snail doesn’t have a proper diet. 

The snail can eat the algae in the tank. However, if you are worried about its health, you can supplement the creature’s diet with flakes, pellets, and blanched vegetables.

You can also follow the Youtube video below, which discusses how to feed mystery snails:

4. Pick The Right Tankmates

Because mystery snails are shy and peaceful, they need non-aggressive tankmates like Cory Catfish, Ghost Shrimp, Nerite Snails, Guppies, and Tetras, to mention but a few.[5]

Aggressive companions such as angelfish may harass your snail and force it to go inside its shell. Generally, I would avoid cichlids at all costs.

5. Allow Your Snail To Acclimatize 

It isn’t enough to ensure that you place a mystery snail right-side-up when you add it to a tank. It is just as essential to ensure that you acclimate the creature to the conditions in the new aquarium:[6]

  1. The average mystery snail comes in a plastic bag. Make sure that the knot around the bag is secure before you proceed.
  2. Place the bag in the new tank. Please leave it to float in the water for half an hour.
  3. Once this period passes, remove a quarter of the water from the bag. Replace it with a similar amount from the new tank.
  4. Do this again after another half hour. Keep repeating this process until the new tank’s water has entirely replaced the bag’s water.
  5. At this point, you can add the snails to the new tank.

If the snails are not properly acclimated, the transition will induce the sort of shock that could make them dormant.

The transition should be gradual, mainly because the snail’s last tank’s conditions are probably different from those it is about to face.

6. Choose The Right Mystery Snail

If you plan on getting new snails in the future, make sure you select the right ones. Buying the healthiest specimens possible will lower the chances that you’ll eventually be disappointed. That means keeping an eye out for the following:[7]

  • Tank – Ignore snails that are housed in enclosures that have dead creatures. The presence of dead fish and snails shows that the conditions in the tank are poor. This also suggests that the living snails in the tank are sick.
  • Appearance – Pay close attention to the physical appearance of the snails. Snails with cracked or damaged shells are not worth your time. Healthy snails have thick shells that are not pitted.
  • Behavior – The healthiest snails are the ones that are either in motion or stuck on a hard surface in the tank. If you don’t want mystery snails that will remain dormant for long periods in your tank, do not buy snails that are already dormant in the store.

How To Tell If Your Mystery Snail Is Dead?

You can tell that your mystery snail is dead by its scent, appearance, and behavior. Dead snails usually release a pungent odor due to decay. Also, dead mystery snails tend to shrink and slide off their shell.

There are ways to determine whether or not your mystery snail is dead, including:

  • Smell – This is the most obvious sign. A dead snail has a bad smell. If your mystery snail is inactive, remove it from the tank. The smell will tell you everything you need to know.
  • Size – Snails tend to shrink in size when they die. They also feel lighter. If you take a snail out of the water and it doesn’t feel as heavy as you remember, and neither is it as large as you expected, it might be dead.
  • Shell – Look inside the shell of the snail. If the shell is empty, you can conclude that the snail died. In many cases, when you lift a dead snail, the shell will fall off because the snail has shrunk in size.
  • Trapdoor – Examine the snail until you find the trapdoor. A snail whose trapdoor is open is most likely dead. If the trapdoor is shut, try pulling at it. If the snail is alive, you should feel some resistance.
  • Light – Turning the lights on can encourage some snails to respond. If that doesn’t happen in your case, try holding the snail up to a light source. In some cases, depending on the thickness of the shell, you can see the heartbeat in a living snail.[8] A dead snail doesn’t have a heartbeat.
  • Relocation – In many cases, moving a snail to a new location is enough to encourage a living snail to become active. A living snail is also more likely to retreat into its shell when you touch it. A dead snail won’t respond to such stimuli.

How Do You Know When A Mystery Snail Is Dying?

You can know when a mystery snail is dying by checking its appearance and behavior. The shell of a dying snail is usually thin, cracked, damaged, and discolored. Also, the snail will refuse to retreat when touched, and in some cases, will be found shrunk outside its shell.

It is difficult to determine when a mystery snail is dying because the signs are not necessarily obvious. Also, the signs don’t always mean that the snail is dying. It could mean that the water conditions are wrong or that the mystery snail is sick. 

The only genuinely damning sign is a snail that is out of its shell. Even if the snail is still alive, it is definitely in the process of dying. A dead snail should be removed from the tank before it corrupts your water.


If your snail has stopped moving, you should first make sure that it isn’t dead. Check if the aquarium smells or if the shell is empty. If that is the case, there is nothing you can do to improve the situation. 

But if the snail is still alive, your first action should be to check the water parameters. Make sure that the pH and temperature haven’t changed.

It would help if you also eliminated aggressive tankmates that might have stressed your snail and forced it to hide.


  1. https://aquariumsphere.com/snail-dead-or-sleeping-aquarium/
  2. https://www.fishkeepingworld.com/how-long-do-snails-sleep/
  3. https://beta-static.fishersci.com/content/dam/fishersci/en_US/documents/programs/education/technical-documents/data-sheets/carolina-biological-aquatic-snail-data-sheet.pdf
  4. https://www.wikihow.com/Care-for-Mystery-Snails
  5. https://www.aquariumsource.com/mystery-snail/
  6. https://animals.mom.com/acclimate-mystery-snails-1739.html
  7. https://www.aquariumcarebasics.com/freshwater-snails/mystery-snail/
  8. https://animals.mom.com/how-to-tell-if-your-water-snail-is-dead-7842036.html