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Why Is My Snail At The Top Of The Tank? (7 Surprising Facts)

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Not once I caught my snails hanging at the top of the tank. At first, I didn’t think much of it and assumed they enjoyed being there.

Over time, I came to realize that this behavior may indicate a more serious underlying issue in some cases.

Hence, I decided to devote an entire article to this subject, with the hope that it proves beneficial. Let’s delve into it right away.

An intriguing photograph capturing an aquarium snail clinging to the top of the glass.

Why Is My Snail At The Top Of The Tank?

Snails may spend time at the top of the tank for various reasons, including taking a breath, searching for food, or finding better conditions. Some snails may also feed or lay eggs at the surface, so this behavior isn’t always a sign of trouble.

Many aquarists panic when their tank’s inhabitants display unusual behavior.

In the case of snails, if you notice them spending more time at the top of the aquarium, you can blame the following:

1. You Have A Land Snail

Snails are not all the same. Experts have discovered a whopping 4,000 freshwater slugs and snails over the years.

Some of them use gills to survive underwater. Others must come to the surface to breathe.[1]

Older groups of underwater snails have two gills. However, the majority have one. This gives them more room inside the shell.[2]

That one comb-like gill allows them to survive beneath the surface by extracting oxygen from the water.

You may also encounter aquatic snails with a lung that pulls oxygen from the air above the surface.

They use a siphon of sorts that traps air bubbles. These air bubbles allow them to remain underwater for long periods without drowning.[3]

Common sense will tell you that land snails live solely above water, but that is not true.

Pulmonate snails are land creatures, and yet they can spend nearly 24 hours underwater before they drown.[4]

What does this mean? Maybe your snail is at the top because it needs to come to the surface occasionally to catch its breath.

The grove snail bears a striking resemblance to aquatic snails and can often be mistaken for them.

If you visit your aquarium at the same hour every day, maybe you only appear when the snail has come to the surface.

Talk to your retailer. Ask them to identify the type of snail they gave you. For all you know, they sold you a land snail even though you asked for an aquatic species.

If you are aware of the type of snail you have, here are ten examples of land snails that are commonly bred and kept by people:

  • Garden snail (Helix aspersa)
  • Giant African snail (Achatina fulica)
  • Roman snail (Helix pomatia)
  • Brown-lipped snail (Cepaea nemoralis)
  • White-lipped snail (Cepaea hortensis)
  • Grove snail (Cepaea nemoralis)
  • Heath snail (Xerolenta obvia)
  • Milk snail (Otala lactea)
  • Banded wood snail (Cepaea vindobonensis)
  • Vineyard snail (Cernuella virgata)

2. Your Snail Is Looking For Food

Some snails will retreat into their shells and float to the surface in the hopes of using the current to quickly navigate to a different corner of the tank in search of food.

This is the fastest way for snails to travel. The technique is particularly useful in the wild, where they have a seemingly endless body of water to traverse.

You should take this tactic in an aquarium as a sign that your snail has insufficient food. Although, snails will also use this technique to escape predators and poor conditions.

But the technique is somewhat useless in an aquarium because they have nowhere to go. The aquarium is a closed system.

Here are five signs that your aquatic snail might be hungry:

  • Active searching behavior: If your snail is actively crawling around the aquarium, it may be searching for food.
  • Grazing on surfaces: If your snail is constantly grazing on surfaces like glass or plants, it may be looking for algae or other food sources.
  • Increased antennae movement: Your snail’s antennae may become more active and move more frequently when it is hungry.
  • Clustering around food: If you place food in the aquarium, hungry snails may cluster around it and start feeding.
  • Weight loss: Over time, if your snail is not getting enough food, it may start to lose weight, indicating that it is hungry.

Pro Tip: I highly recommend API Algae Eater Wafers (link to Amazon) for your aquarium. They meet the nutritional needs of algae-eating fish and provide a healthy and balanced diet for aquatic snails.

Certain types of snails take pleasure in feasting on the algae that cling to the upper sections of the tank.

3. The Snail Wants to Escape An Unconducive Environment

Don’t expect every snail to float away when you expose the creature to low-quality conditions. Some of them will simply climb to the surface.

If you have room above the water level, the snails will stay at the top to escape the unconducive situation below. Some will even try to get out of the tank.

You can make a snail unhappy by allowing extreme temperatures and the wrong pH and hardness to persist.

Obviously, each snail has its own water requirements, but the following guidelines are typically recommended for aquatic snails in general:

  • Temperature: 20-28°C (68-82°F)
  • pH: 7.0-8.0
  • Ammonia: 0 ppm
  • Nitrate: < 20 ppm
  • Nitrite: 0 ppm
  • Water hardness: 5-15 dGH

To measure these parameters, I personally use the API FRESHWATER MASTER TEST KIT (link to Amazon).

I love this bundle because it is highly accurate and last for about eight hundred measures, making it extremely cost-effective.

4. The Oxygen Content Is Low

Oxygen enters the tank through the surface. Therefore, the top layer is the most oxygen-rich.

If oxygen levels below deteriorate because of high temperatures, overcrowding, ineffective filters, and the like, the snail will head to the top where the oxygen content is higher.

Don’t forget that many aquatic snails have gills that extract oxygen from the water. Low oxygen levels in an aquarium will directly influence their well-being.

Below are five visible signs indicating your snail doesn’t get enough oxygen:

  • Slow or lethargic movement
  • Reduced appetite or lack of interest in food
  • Gasping at the surface of the water
  • Floating upside down or sinking to the bottom
  • Clinging to objects near the water’s surface

The easiest way to increase the oxygen concentration in your tank is by installing an air stone.

Simply put it in the middle of the tank where objects don’t block the bubbles.

In my personal experience, I opted for the Hygger Aquarium Air Stone (link to Amazon), which not only efficiently oxygenates the tank but also operates quietly.

Incorporating an air stone into your aquarium setup is a crucial step in enhancing the oxygen levels of your tank.

5. Your Snail Is About To Lay Eggs

Katherine C. Horn, Evan Siemann, Kate M. Boles, Sally D. Johnson, Christopher A. Gabler, and Anthony Moore wrote an interesting paper (Wetlands Vol 28).[5]

They noted that golden apple snails lay eggs out of the water to avoid predators and increase hatching success.

You see this behavior in many freshwater snail species, including mystery snails. With saltwater snails, you may find the eggs behind a rock.[6]

Again, a conversation with your local retailer will tell you volumes about the habits of the snails you bought and whether you can expect the creatures to lay their eggs above water.

Here are a few visible signs indicating that your snail is about to lay eggs:

  • Your snail will display increased activity by moving around the tank more frequently.
  • The snail’s body will become more rounded and swollen than usual.
  • Excessive mucus secretion will be noticeable, as snails use this substance to attach their eggs to a surface.
  • Your snail will attach itself to an egg-laying surface, such as glass or a plant, to deposit its eggs.
  • The snail will exhibit unusual reproductive behavior, such as crawling upside down or twisting its body into odd positions.
Aquarium snails lay their eggs above the water line to prevent the suffocation of the developing embryos.

6. Your Snail Tries To Avoid Aggressive Fish

If your snail shares the tank with aggressive tankmates, it is very likely that it will climb to the top trying to avoid them.

Here are a few signs that may indicate that your snail has previously encountered an unpleasant fish:

And here is a list of aggressive fish species that shouldn’t be mixed with aquatic snails:

  • Oscar (Astronotus ocellatus)
  • Jack Dempsey (Rocio octofasciata)
  • Green Terror (Andinoacara rivulatus)
  • Red Devil (Amphilophus labiatus)
  • Pike Cichlid (Crenicichla spp.)
  • Peacock Bass (Cichla spp.)
  • Arowana (Osteoglossum spp.)
Due to their highly aggressive nature, it is not recommended to keep Green Terror fish in the same tank as snails.

7. The Snail Is Simply Eating

Some snails will float at the surface to quickly navigate to new sections of the aquarium.

Others will climb to secure the food you added at the top. The floating technique can also work in this situation.

Snails don’t discriminate where food is concerned. They will eat whatever they can find in the water. That includes dead and decaying matter.

The snails may rise because they’ve noticed your movements at the top and have grown to associate your presence with food.

In this case, the snail will likely climb back down after finishing its meal and not remain at the top for an extended period.

Is It Normal For A Snail To Be At The Top Of The Tank?

Surprisingly, yes, this behavior is normal.

Don’t forget that many snail species lay eggs above the water level. And if you sprinkle food at the top, they have every reason to ascend.

Snails are scavengers. They will go wherever they can find food. As such, their presence at the top is perfectly normal.

But what if you don’t see eggs at the top, and all the food is at the bottom? Is it still normal for the snails to frequent the top? Well, yes, it is.

Some snails simply prefer the top. Like human beings or even fish, they have unique attributes. You don’t have to panic unless the snails give you a reason to worry.

When Should I Be Worried About My Snail Staying At The Top?

You should worry when you see concerning symptoms such as lethargy and loss of appetite. Snails will flee from low-quality water.

Therefore, you should also worry if you test the water and record high temperatures, dangerous ammonia concentrations, low calcium levels, etc.

Can A Snail Fall From The Top And Get Hurt?

Every creature that climbs to a high point risks falling back down and getting hurt. Snails are no different.

They have shells that provide added protection. However, those shells can break when the snail collides with decorations or objects like filters.

Snails cannot survive out of their shells. In fact, a broken or cracked shell can cause the snail to dry out.

Not only do snails grow their shells (by generating layers of calcium carbonate), but the creatures are attached to their shells.[7]

The shell is as important to the snail as any other organ. Therefore, a broken shell is your biggest concern.

If the shell survives the fall, the snail may land upside down. Snails in such situations can push themselves right-side-up, but only if they land on a stable surface.

A snail that falls upside down in the sand is more likely to die.[8]

Although uncommon, it is possible for aquarium snails to fracture their shells if they fall from the top of the tank.


If you’re in a hurry, here’s a quick rundown of the key points mentioned above:

  • The behavior of snails in an aquarium can indicate various things such as the need to come up for air, search for food, escape poor conditions, or due to low oxygen levels.
  • There are different types of snails that can be kept in an aquarium, and some of them need to come up to the surface to breathe while others can survive underwater.
  • Snails use floating to navigate their environment, enabling them to locate food and evade predators or unfavorable conditions.
  • Poor water conditions such as high temperatures, low oxygen levels, and the wrong pH and hardness can make the snail unhappy, and it may head to the top where the oxygen content is higher.