Tiny Snails in Fish Tank (Infestation) – What to do

Snails are a great addition to the aquarium but only in moderation. At times, out of nowhere, you might see some little snails that you did not put in your tank. Where do they come from?

Tiny snails or snail eggs get into fish tanks hiding in plants, rocks, and decorations. To keep them at bay, quarantine new aquarium plants, feed fish less, manually remove them, use a snail trap, snail-eating pets, or snail-killing chemicals. Use chemicals that won’t harm snails or other aquatic life.

Snails are partly beneficial to the aquarium ecosystem but can be a nuisance because they reproduce in large numbers within a short time, causing stress to fish.

Snails in aquarium

Tiny snails in a fish tank – what are they?

When setting up a tank, you get a tank large enough for your pets and maybe a little more space. When these tiny snails infest such a tank, it will get overcrowded, causing stress to the fish. The snails will likely reproduce in large numbers and overrun the tank.

Unfortunately, these tiny snails will always find their way into the tank. They will sneak in hiding on decorations, new plants, or rocks. They will either come as young snails or as eggs, and it will take time before you notice them because they will burrow in the substrate and only come out when the lights are off.

Some of the invasive pest snails include:

1.  Malaysian trumpet snail (melanoides tuberculata)

These are freshwater snails that grow to a maximum size of 1.4 inches. They vary in color according to their respective species. They can be brown, gray, cream, or yellow.

Some have dark red or brown patterns on their shells. They have long conical shells with rings that look like ice cream cones.

When young, they spend most of their time burrowed in the substrate and will come out at night. They feed on algae, fish leftovers, and dead plants. They are parthenogenetic, meaning they can reproduce without a male.

2.  Mini Ramshorn snail (Planorbis Arnoldi)

The mini ramshorn snail is very similar to the great ramshorn snail kept in aquariums. However, it is small and can grow to a maximum of ¼ inch.

They are hermaphrodites meaning two snails of any sex can breed. They also reproduce quickly and will overrun the tank in a short time. They are excellent scavengers that feed on rotten plants, leftovers, and algae. 

3.  Bladder snail (Phsella Acuta)

They have a dark yellow or brown shell with yellowish speckles and spirals to the left. The snail grows to a maximum of 0.6 inches. It is omnivorous but mainly feeds on algae.

Bladder snails reproduce by laying eggs in the canister filter, and their babies can clog the filter.

4. Pond snail (Lymnaea Stagnalis)

They are freshwater snails that can grow to 1 – 2.5 inches. They are dark or light brown and are more active at night. They feed on algae, decaying plants, and fish leftovers. They are hermaphrodites.

5. Pet snails

Pest snails, like mystery snails, are useful to some extent to the aquarium ecosystem because they will clean up algae, dead plant matter, and fish leftovers.

However, they overrun the tank within a short time, making it inhabitable for the fish. The following factors contribute to their large population:

  • Overfeeding the fish.
  • Massive algae growth.
  • Presence of decaying plant matter.

What to do about aquarium snail infestation

Snail infestation is a headache no aquarist wants to experience, but we can hardly avoid it. Below are the measures to control snail infestation in your fish tank:

1. Quarantine new plants

Since the snails will get into the tank by hiding on plants and decorations, you can quarantine the plants in a separate tank, look for the snails and eggs, and remove them. You can use a snail-killing chemical and remove them if they are in large numbers.

For rocks and other decorations, you can clean them with running water until you remove any snails or eggs. Put them in the fish tank when you are sure they are clear of any snail or their eggs.

2. Do not overfeed your fish

Pest snails, just like mystery snails, feed on algae and fish leftovers. Feeding your fish food they can consume in less than 5 minutes will ensure there are no leftovers for the pest snails.

That way, you will limit their reproduction rate even if they are in the tank.

3. Manual removal

You can manually remove unwanted snails and give them away to a person with a snail-eating pet or return them to the pet store. Some aquarists will crush them to a quick death.

4. Buy a snail-eating pet

Bringing in a snail-eating fish (like kuhli loaches) or snails can be a long-term solution to snail invasion. However, it will only work if the predator can keep up with the little snails and if you plan to keep the predator too.

However, if you have other pet snails in the tank, they might be eaten too. The assassin snail is cut out for the job.

5. Snail trap

You can trap pest snails in several ways, and traps are available in pet stores. If you drop a piece of cucumber into the tank at night, the pest snails will come out to eat it. You can remove the cucumber and the snails. 

You can also use a container with a lid with holes only big enough for the snails and put a cucumber inside to draw them to the container. Ensure the holes are not big enough to fit a fish or the snails when full. You can remove the snails and dispose of them as you would if you removed them manually.

6. Snail-killing chemicals

You can also use chemicals meant to kill invasive snails. However, you need to be careful because they might affect sensitive fish. Don’t use chemicals if other types of snails are in the tank.

Are snails in a fish tank good?

Snails are wonderful creatures to add to a fish tank because they add so much color. Breeds such as mystery, nerite, and apple snails are lovely to keep. However, no one will appreciate the presence of invasive snails in a fish tank.

The good side of snails

  • Help aerate the substrate: Most pest snails will burrow in the substrate. This will help prevent harmful gas buildup.
  • Cleaning the tank: Snails will feed on algae, fish leftovers, and decaying plant matter aiding in cleaning.

The ugly side of snails

  1. They are prolific breeders and will overrun the tank in a short time.
  2. They release a lot of bioloads, meaning you will have to clean the tank more often.
  3. In their large numbers, they will feed massively on algae competing with other algae-feeding pets.
  4. Most of them will clog the filter, intake strainers, and impellers.


Invasive pest snails will enter the tank hiding on plant leaves, decorations, and rocks. They will feed on algae, fish leftovers, and decaying plants. Although they are an excellent clean-up crew, they will reproduce in large numbers and overrun the tank. 

To eliminate them, bring in a snail-eating pet, remove them manually, use a trap, or use snail-killing chemicals.

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