Do Mystery Snails Eat Fish Eggs? What to Know

Keeping fish and mystery snails in the same tank is beautiful because they both have radiant colors that will add so much beauty to the aquarium. However, if you plan to breed your fish, this might not be a good idea because mystery snails will eat the fish eggs.

Although mystery snails are known to be docile creatures that will coexist with any aquatic pet, they are also opportunistic feeders, and fish eggs will be a good delicacy. A mystery snail feeding on fish eggs is dangerous because the fish will obviously attack it. Let’s look at why this happens and what you should do.

Why will Snails Eat Fish Eggs?

Snails are opportunistic feeders and will eat fish eggs and even their own eggs. Some snail species are more aggressive than others, and you should research the snail behavior before adding it to your tank. Some snail species will even eat fish fry. The following are reasons why a snail will eat fish eggs.

1. Hunger

Mystery snail eating habit can surprise you. They love eating and when hungry the snail will eat almost everything. So when keeping snails in an aquarium with fish, ensure you feed them regularly to minimize the chances of eating fish eggs.

2. Calcium deficiency

Snails require a lot of calcium to grow and maintain their shells. Eggs are a good source of calcium, and snails will eat them to quench their calcium craving.

3. Type of snail

Some snails are aggressive feeders and will prefer to feed on fish eggs. Therefore, you should research the eating habits and preferences of the type of snail you wish to add to your fish aquarium.

How to Keep Fish and Mystery Snails in the Same Tank

It will be important noting the the following as you prepare to keep your snails and fish together:

1. Water parameters

Different fish require different water parameters. Therefore before adding the fish to a tank with mystery snails, ensure they prefer the same water parameters. Mystery snails require a temperature of 21 – 28 degrees Celsius, the water hardness of 150 – 300 ppm, and a pH of 6.5 – 7.5.

Choose fish that can live in the same water conditions. Mystery snails and betta fish are always a good compatible to keep in your tank.

2. Compatibility

Mystery snails are peaceful and will not attack fish. However, some types of fish are spooky and will eat mystery snails. Choose a peaceful kind of fish. Bigger fish are not a good choice because they can swallow mystery snails easily.

Some small fish will also try to swallow the mystery snail and choke. Below are some suitable tank mates for mystery snail.

  • Tetras
  • Guppies
  • Shrimp
  • Killifish
  • Livebearer

3. Tank size

Mystery snails love to explore and will feed on algae and biofilm. It would be best to keep them in a sizable tank that will grow enough algae to feed. Experts recommend keeping a maximum of two mystery snails in a five-gallon tank.

Therefore if you decide to add fish to the tank, ensure the tank is big enough. I recommend having a 20-gallon tank to give both the fish and mystery snail enough space to explore.

4. Feeding

Mystery snails are slow and less aggressive compared to fish. Therefore if you feed them together, the mystery snail will starve because the fish will feed quickly and will also prevent the mystery snail from feeding.

It is best to have a feeding program where you feed the fish during the day. Since mystery snails tend to sleep all day and become active at night, you can drop their portion during the night.

The feeding program will allow the mystery snail to feed without much disturbance from the fish. Ensure the tank has enough algae and biofilm for the mystery snail to feed. This will lower your mystery snail feeding budget.

How to Protect Fish Eggs from Snails

There are a number of ways you can save fish eggs from being eaten by your snails:

1. Feed your Snail Regularly

Feeding your snail with enough food can tame its desire to eat fish eggs. If the snail is a herbivore, ensure there are enough plants, algae, and biofilm in the tank.

2. Give Sufficient Calcium to your Snail

Ensure there is enough calcium concentration in the water in the tank. You can increase calcium concentration by water mineralization or adding calcium supplements.

If your snails are herbivores, feed them with calcium-rich vegetables like lettuce, zucchini, spinach, kales, cabbage, and broccoli. You can also feed them with cuttlebone because it also contains other essential minerals.

3. Provide a Safe Place for Fish to Lay their Eggs

You should provide a safe place for the fish to lay their eggs early enough, even before they start mating. The ideal place to lay eggs will vary depending on the type of fish and where they prefer to lay their eggs.

●     Fish that Lay their eggs in aquatic plants: Ensure to add some nice aquatic plants where the fish can lay eggs and protect them from the snails.

●     Fish that bury their eggs: Ensure to add enough substrate into the aquarium that the fish will use to bury the eggs. However, if you have an assassin snail in the aquarium, you will have to move it to a separate tank because they also hide in the substrate, and they may uncover the eggs.

●     Fish that hide their eggs on rocks caves: Add rocks to the aquarium to ensure they get a suitable place to hide their eggs.

4. Move the Snails to a Separate Tank until after the Eggs Hatch

If you have an extra tank, then moving the snails would be a wise decision. This way, you will be guaranteed no snail will eat the fish eggs. You can put back the snails in the parent tank after the fish eggs have hatched. Carnivorous snails should not be put back because they will eat the fry.


If you decide to keep fish and snails in one aquarium, you should first understand their behavior and eating habits. Some fish will eat snails, while some snails will eat fish eggs and their fry. Before purchasing, also enquire about their compatibility.

Mystery snails are peaceful and will hardly harm any other creature in the tank. However, they will feast on fish eggs. If you are planning to breed your fish, then you need to take the precautions mentioned above to ensure the mystery snails do not feed on fish eggs.


  1. United States Department of Agriculture AgResearch Magazine, Protecting Fish Eggs From Fungus
  2. Golden Sands Resource Conservation & Development (RC&D) Council, Aquatic Invasive Species

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