Why Are My Cory Cats Swimming All Over Tank

Cory cat is a shorter way of addressing Corydoras catfish. Cory cats are active species of fish that use their behavior to exhibit how they feel. Keeping Cory cats is effortless if you can read their behavioral signs.

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Why Are My Cory Cats Swimming All Over Tank? Cory cats swimming all over the tank is a behavioral expression. One of the significant reasons why Cory cats swim all over tanks is because of stress. It can also mean the fish are not happy with their environment for one reason or the other.

You might see your cory cats doing the following

  • Swimming All Over Tank
  • Cory Catfish Glass Surfing
  • Swimming Up and Down Tank
  • Swimming at Top Of Tank

Cory cats might not be happy in their environment for one reason or the other such as

  • Overfeeding
  • Overcrowding in their tank
  • Poor water quality
  • Poor tank conditions

Why Are My Cory Catfish Swimming Up and Down?

It is very common for a cory catfish to swim up and down in a tank, they usually do this because they can see themself in the reflection and are trying to work out what the reflection is.

The cory will also swim up the tank to get air / oxygen.  They also swim up and down just for fun.

Another cause can be that they are ready to breed and this is one way that they show it.

Why Are My Cory Catfish Swimming at the Top of My Tank?

If there is a lack of oxygen in your tank your cory catfish will sim to the top of your tank to the surface to breath.  There will also be more oxygen in the water at the top of the tank.

Cory Cats Swimming All Over Tank

If your fish are constantly swimming at the top of your tank you will need to check the water conditions with a testing kit (Available on amazon) to make sure all conditions are within tollerance.

You should also add an air pump (Available on Amazon) to your aquarium to make sure the water has enough oxygen in it.

What to Do When you Find Cory Cats Swimming All over the Tank

Glass surfing is a term the most aquarists use to describe the occasion of fish swimming up and down in the tank. It is one of the behavioral ways Cory Cats express how they feel at a particular time.

Often, your Cory Cats swimming all over the tank isn’t something to worry about. In some instances, glass surfing is expected in Cory Cats.

Some of the instances that you can expect your Cory Cats to swim all over tank include; when you introduce them to a new environment when you finish performing a significant water change, when you are close to the tank, and the fish are expecting food, or when you make a substantial change in the water parameter of the container.

However, if all these do not apply to your case, you can evaluate the tank parameters. You should ensure that all the tank parameters and conditions are suitable and favorable for your Cory Cats.

Nevertheless, you can find Cory Cats swimming all over the tank even when all these conditions are favorable. While you keep evaluating the parameters, you might not have anything to worry about.

It is essential to know that fish can act in all sorts of random and funny manners. You can continue experimenting and evaluating to establish the reason for their behavior. While these last, the best thing to do is ensure that the tank conditions are favorable for the fish.

Habitat Parameters and Suitable Tank Conditions for Cory Cats

It is not challenging to keep Cory Cats in your aquarium. They are hardy and can cope with tank conditions that are not extreme. Also, importantly, the feeding demand for Cory Cats is not tasking.

Cory Cats are hardy enough to be stable in community tanks. They can cope with non-aggressive tank mates of similar size.  Some aquarists prefer to call Cory Cats an armored fish because they have bone-like plate materials that run through the length of their body.

The tank demands of Cory Cats are similar to that of other freshwater fish. Hence, they form a good member of community tanks. Cory cats always appear healthy and alert when they are happy in their tank.

Cory Cats are bottom dwellers. Therefore, they love to have gravel or substrates at the base of their tanks. You can add about 2 inches of gravel to your Cory Cat tank.

Also, Cory Cats are lovers of live plants. Including live plants in their tank will provide them with hiding places for them to rest. Likewise, other decorations offer space for the fish to explore; hence, it keeps them happy.

Also, the tank condition demands of Cory Cats are not extreme. They can even survive and thrive in an established tank. They often explore a considerable range of water conditions.

Cory Cats prefer to live in an aquarium with a pH range of 7.0-7.8. They also thrive in tanks that are within the temperature range of 72-78°F. They can cope with parameters that fall within this range.

It would be best if you prevented the accumulation of toxic compounds in the fish tank. Ensure that you keep the nitrate and ammonia level of the tank at 0ppm. Likewise, avoid making a sudden change to the environmental conditions of the fish tank.

General Behavior of Cory Cats

Cory Cats are the peaceful species of aquarium fish. They are certainly one of the most desirable species when it comes to temperament and aggressiveness. They are the most suitable beginner catfish option because it is easy to take care of them.

Cory cats are accommodating and endearing. Thus, they usually don’t have any problem living with other fish in a community tank. They don’t fight back, so don’t keep them with aggressive fish.

Cory Cats can cope with almost any non-aggressive species in their tank. Some of the suitable tank mates for Cory Cats include other Cory, Swordtails, Tetra, and Otocinclus Catfish. They can also cope with non-fish tank mates like different species of snails and shrimps.

You should avoid keeping your Cory Cats with certain species of fish such as Cichlids, Oscars, Texas, and Jack Dempsey. These species can give your Cory Cats a tough time if you keep them together in the same tank.

However, it would be best if you did not mistake the calm behavior of Cory Cats for being boring. This species of fish are colorful and active; thus, making them a good species. They also exhibit specific amusing and funny movements that can add life to your tank.


Cory Cats offer a good option for beginners that are looking to introduce Catfish to their fish tank.  This species of catfish are not aggressive, hardy, and easy to care for. They also have a significant adaptive ability as long as the change is gradual.

However, Cory Cats can sometimes exhibit some funny movements like glass surfing. When this happens, the first thing you should do is check your tank parameters and ensure that the fish are not stressed.

Also, importantly, you should only keep Cory Cats with suitable tank mates. Keeping them with aggressive and rough species can make the environment uncomfortable for them.