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Do Cory Catfish Eat Snails? (And How To Make Them Coexist)

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Since Cory catfish are scavengers, one of the most frequent questions people ask is whether they eat snails. As I started growing Corydoras, I even asked this myself. Fortunately, after a few months of observations and research, I came to a conclusion.

Cory catfish do not eat snails because they cannot fit in their mouths. Corydoras have suckers for mouths, allowing them to scavenge for food at the bottom of the tank. However, they don’t have the tools to eat a living snail in its shell. Yet, Corydoras may eat dead or baby snails.

As we proceed, I will take you step-by-step on how to make Corydoras and snails coexist in the same tank. That includes adjusting the water parameters using dedicated kits. Then, I will discuss how Cory catfish will deal with dead and baby snails.

Do Cory Catfish Eat Snails?

No, Cory Catfish do not eat snails. Some aquarists may question that conclusion because, from what they have learned, fish are opportunistic feeders. They will eat whatever they can fit in their mouths.

These individuals will argue that, in the right circumstances, a cory catfish can eat a snail. But if you consider the factors below, you will understand why that reasoning cannot apply to cory catfish:

1. Cory Catfish Are Peaceful

If you look at any list of suitable tankmates for cory catfish, you will notice that it includes a multitude of snails.[1] This is because cory catfish are friendly and peaceful. They can coexist with other peaceful creatures. That includes snails.

They do not have a reputation for attacking their neighbors, regardless of their size. In fact, Cory catfish are similar to snails because both creatures are scavengers.

You will find Corydoras feeding next to snails and other tankmates during mealtimes. This tells you something important. Not only are cory catfish unlikely to eat their tankmates, but the creatures are not intimidating in any way.

2. Corydoras Rarely Fight Over Food

A scarcity of food can encourage aquatic creatures to fight one another. Some fish have such voracious appetites that they will compete with each other even when the tank has abundant food.

For that reason, aggressive fish with the same dietary preferences are more likely to fight during mealtimes. Cory catfish are scavengers, just like snails. But their peaceful temperament prevents them from fighting for or even stealing food from their neighbors.

Snails are the same. Rather than fighting for food at the surface, they will look for food at the bottom and in the various corners of the tank.

3. The Cory Catfish’s Mouth Is Too Small For Snails

At the end of the day, temperament doesn’t mean everything. Fish are unpredictable. Even with a rich diet and a well-maintained tank, peaceful species can turn on their neighbors without warning, either eating them or bullying them to death simply because they feel like it.

What makes professional aquarists so confident that a cory catfish will not eat the snails in the aquarium? It’s simple. Cory catfish have suckers for mouths. Those mouths are too small to eat snails.

This is why cory catfish are such great additions to most tanks. They won’t attack other fish, not even smaller fish, because their mouths won’t permit the Corys to eat those fish. Your snails are perfectly safe. A cory catfish cannot extract a snail from its shell.[2]

4. Corys Are Not Much Bigger Than Snails

You have to keep the size difference in mind. Large fish are dangerous because they will eat any small creature that fits in their mouths. But the size difference between Cory catfish and snails is too small. In fact, in some cases, the snails are bigger.

Cory catfish have an average size of 1 to 4 inches. But a lot of them are 2 inches. The most popular aquarium snails fall somewhere within that range as well.

To a snail, a cory catfish is not big enough to pose a threat. Don’t forget the shell. It is roughly 1/6th of an inch.[3] It is too big for a cory catfish to eat. 

5. Corydoras And Snails Share Similar Requirements 

It should be noted that cory catfish and freshwater snails can survive in the same aquarium. Freshwater snails require water with temperatures of 65 to 82 degrees F and a stable pH.[4] 

Naturally, the exact temperature will vary depending on the snail. But most species tend to fit within the same range. This allows them to thrive in Cory Catfish aquariums. 

The fish demand temperatures of 74 to 80 degrees F and a pH of 7.0 to 8.0.[5] You don’t have to worry about harming the snails by changing the parameters to suit the cory catfish or vice versa.

In Which Cases Cory Catfish Might Eat Snails?

As you can see, professional aquarists have very good reasons to dismiss cory catfish as a potential threat to snails. Everything from their small size to the shape of their mouths makes the prospect of eating a snail either incredibly difficult or completely impossible.

If your cory catfish ate your snails, those snails had already perished. Cory catfish can eat dead fish flesh.[6] Dead snails are just as appealing to them. When a snail dies, the body may fall out of the shell.

If the cory catfish comes across the remains of a dead snail whose body has fallen out of its shell, the fish may eat the snail. 

Also, you can feed a snail to cory catfish. But you have to crush the snail beforehand. Outside of these specific situations, a cory catfish will not eat snails. Cory catfish and snails can live together.

How To Make Cory Catfish and Snails Coexist?

Cory catfish and snails can live peacefully in the same tank. But if you want, you can take the following steps to enhance their peaceful coexistence:

1. Adjust The Water Parameters

I highly suggest maintaining parameters that suit both creatures. As was noted above, Cory Catfish require 74-80 degrees F and a pH of 7.0-7.8. A tank whose parameters can accommodate cory catfish will also appeal to most freshwater snails.

Also, make sure that the ammonia, nitrates, and nitrites are about 0 ppm. To measure these, I use the API Water Test Kit (link to Amazon). That is probably the most accurate bundle out there. Within a few minutes, you’ll know if something went wrong with your water.

2. Pick A Relatively Large Tank

Cory catfish should be kept in a tank of 10 gallons, at least. For the best results, aim for 20 gallons. They need a long, shallow aquarium. Depending on the species, you can keep snails in 5 gallons of water.

But the more snails you have, the bigger the tank you need. A small tank will irritate your fish and their tankmates, making them more likely to act aggressively towards one another.

Small tanks can also encourage toxins to accumulate. A spike in toxins like ammonia will harm both cory catfish and snails. If the ammonia doesn’t kill them, it will make them more susceptible to illnesses. Those that survive may develop hostile mannerisms because of the stress.

The tank that I use is the well-known Tetra Aquarium 20 Gallon Fish Tank Kit (link to Amazon), which I also reviewed here. That bundle features the perfect balance between quality and cost. If your aquarium is too small, I highly recommend checking it out.

3. Perform Routine Water Changes

Many people perform water changes during emergencies. For instance, when the ammonia concentration spikes. However, you should perform water changes before the ammonia levels rise to a point where you need a large water change to dilute the toxins.

I suggest doing weekly water changes of 30 percent to keep the aquarium clean. A clean aquarium protects cory catfish and snails from diseases and the consequences of high ammonia levels.

Like humans, the creatures are more likely to behave in a clean environment. This is why it is just as important to install a filter. Water changes are essential, but they must work in tandem with a decent filter to keep the conditions in the aquarium from deteriorating.

4. Introduce A Few Plants

Plants are vital. Besides oxygenating the water, they provide hiding places. This allows both snails and cory catfish to feel safe, especially if their tank has larger, more aggressive fish.

You can use artificial plants if you want. But don’t be afraid to experiment with natural varieties as well. The cory catfish may nibble on them from time to time, but they won’t eat the plants. Again, the design of the creature’s mouth makes such tasks difficult. 

5. Feed Your Creatures Properly

This goes without saying. Keep the cory catfish and snails well fed. Yes, cory catfish are scavengers that can eat algae. But if they don’t have enough leftovers, detritus, and algae in the tank, they will starve. Give them pellets, algae wafers, bloodworms, daphnia, and the like where necessary.[7]

Snails are the same. If their tank doesn’t have enough detritus and algae to satisfy them, supplement their diet with external food sources. But you should only give them what they can finish in three minutes or less.[8]

6. Pick The Right Tankmates

Cory catfish cannot live alone since the depression will kill their appetite. They will essentially starve to death. If you want to add other creatures to their tank, on top of snails, aim for non-aggressive tankmates like Glass Tetras and Otos.

Cory catfish and snails can live with one another because they are both harmless. They cannot fight back against larger enemies, which makes them a target for bullies. 

Do Corydoras Eat Baby Snails?

Some people say that Corydoras catfish can eat small snails.[9] They can also eat snail eggs. This makes sense. The fish won’t eat adult snails because both creatures are more or less the same size. Additionally, a catfish’s sucker mouth cannot reach a snail hiding in a shell.

But a tiny baby snail that fit in a catfish’s mouth. This does not guarantee that your catfish will eat the baby snails and eggs in the tank. But it can happen. Keep this in mind if the survival of your snails and their eggs matters to you.

Will Corydoras Eat Dead Snails?

Corydoras catfish will eat dead snails. Many aquarists feed dead snails to catfish. But they crush them first to make them easier to eat. Because catfish are scavengers, they can also eat the dead snails they find in the tank.

This is a good thing because those dead snails will rot. This will produce ammonia which, as you now know, is bad for the aquarium. The best thing would be for the Corydoras catfish to eat all the dead snails. 

But you shouldn’t rely on these creatures to keep your tank clean. Take the dead snails out. If your catfish are hungry, crush a few of the snails and throw them back in. Remove the snail remains if the catfish refuse to eat them.

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Conclusions

Cory catfish cannot eat living snails since they are too big to fit in their mouths. But they can eat tiny snails or dead ones, which is good for the tank. But you should still remove the snails when they die. Corys cannot clean the tank on their own.

If you wish to grow Corydoras and snails in the same tank, you should adjust the water parameters and give your creatures some hiding spots. A good filter that prevents ammonia spikes is also essential.

The biggest advantage of Cory catfish and snails is that they are not enemies. Combining these two creatures can foster a flourishing tank where you have complimentary algae eaters and scavengers.

References

  1. https://aquamovement.com/best-cory-catfish-tank-mates/
  2. https://aquariumgravel.com/species/fish/corydora/do-cory-catfish-eat-snails-and-shrimp/
  3. https://aqualifehub.com/do-cory-catfish-eat-snails/
  4. https://www.petco.com/content/petco/PetcoStore/en_US/pet-services/resource-center/caresheets/freshwater-snails.html
  5. https://www.aqueon.com/resources/care-guides/corydoras-catfish
  6. https://en.wikipedia.org/wiki/Corydoras
  7. https://www.vivofish.com/corydoras/
  8. https://www.wikihow.com/Take-Care-of-an-Aquatic-Snail
  9. https://pethelpful.com/fish-aquariums/Freshwater-Fish-that-Eat-Snails