Can You Have Fish While Also Having A Cat?

So, you have a fish tank and thinking of getting a cat? Or you have a cat thinking of getting a fish tank? Cat eats fish, as we see in the cartoons so is it really wise to combine these two pets?

Can you have a fish tank with a cat? You can have a fish tank with a cat. Be sure the cat is not able to get to the tank by having a lid on the tank and prevent the cat from getting to it.

It’s all about preventing the fish and the cat to get in contact with each other. There are different ways of doing it though. And they both could actually harm each other!

How cats affect the fish

The fish are in an enclosed environment and have nowhere to go. They are also very small, at least most fish that you keep at home are.

Cats on the other hand are free to move and are a lot bigger than fish.

This makes the cat a natural threat to the fish.

The fish can see through the glass, so when a cat is sitting in front of the glass they see it. And what happens if you see a threat? You get stressed. Your fight or flight system is getting active!

Stress is very harmful to the fish. It’s the most common cause of death in fish.

Not only is it stressful for the fish while seeing the cat. It’s also very stressful for them while the cat is scratching the glass of the fish tank or jumps on top of the tank.

The fish doesn’t know it swims in water so it thinks the thing approaching is some sea creature trying to eat it up. Also, the sound the cat is making while landing on the fish tank (or inside the fish tank if you have no lid) is freaking the fish out.

The dangers for both fish and cats

There are some dangers of keeping the two together. And that’s for both the cat and the fish.

For the fish, it’s mainly the stress that is the danger. As I have mentioned before is stress the most common cause of death in fish tank fish.

Even though the fish is not able to jump out and harm the cat, the fish tank could be dangerous for the cat.

Some fish tanks don’t have lids. That’s because some tanks need to be cooled down and by keeping the lid open or some want plants growing out of the tank due to some aquascaping.

This could make the cat fall into the water. This is not good for either fish or cat. The fish will get very stressed by this and also the cat.

You see, cats don’t like water. Not take a bath at least and the cat doesn’t understand there is a tub of water it is about to jump into.

In the water, there are bacteria too, which could be a risk for the cat. If the cat has a small wound it could get infected and be potentially deadly for the cat.

After getting into the water, the cat will most likely clean itself. It will clean itself by licking its pelt and that is also risking the bacteria from the fish tank to get into the cat.

There are also some risks with the claws of the cat. The cat wants to look into the fish tank. A problem for the cat is that the fish tank is quite high up.

This forces the cat to stand on its back legs and lean against the glass of the tank. While looking into the tank the cat wants to play with the fish and is doing it with its paws.

The problem with this is not only that it’s stressful for the fish, but it’s also making scratches in the glass.

The risk with scratches is that it could spring a leak. That’s not good for anyone! Not for the fish, cat, or yourself.

This is a bigger risk with acrylic tanks. The plastic is more prone to scratch and break. Therefore it’s crucial to have a glass tank while having a cat.

The glass tank will get scratched too though.

The last risk is that the tank is falling over on the cat while the cat is climbing and exploring the fish tank.

This is not as big of a risk as you might think. As long as you don’t have a very small fish tank. That’s due to the weight of the fish tank while filling up. Except for the weight of the tank itself, stones, and everything you put into the tank (which could be heavy) you also fill it with water.

Water weighs almost 9 lb per gallon (1 kg per liter). If you have a 55-gallon fish tank (200 liters) the weight of the water you fill the fish tank with will be near 500 lb (200 kg).

That’s too much even for the biggest cat to move!

How to eliminate the risks

It might not sound like a good idea to have cats and fish while reading this. But you can prevent all these negatives by utilizing some simple measures.

First of all, be sure to have plenty of hiding spots for your fish in your fish tank. This is not a solution for every type of fish though.

Some fish doesn’t want a lot of stuff to hide behind. they will move rocks and they will tear up the plants.

These types of fish are not suitable to have together with a cat, due to the risk of them getting really stressed. But those fish are not the most common types.

The most common types (actually almost every) of fish want some places to hide. Be sure to provide it to them so they can get away while feeling threatened.

Be sure the fish tank is on a stable surface. Have a stand specifically made for the tank. That way you are certain the fish tank will be staying where it is, even if a cat is hanging in it.

Prevent the cat from getting to the tank

Also, be sure to have a lid on the fish tank. This will protect the cat from getting into the fish tank. But it could still stress the fish if the cat gets on top of the fish tank so also, be sure to not have launch pads for the cat to jump onto the fish tank.

But cats are very agile and some might even jump from the floor up on the fish tank.

To prevent this, be sure that your cat is not able to get to the fish tank in the first place.

Have your fish tank in another room which the cat is not able to get into. Have some sort of blockage for the cat preventing it from reaching the fish tank.

This will also prevent the cat from scratching the surface of the tank.

Be sure the cat is not around when you making water changes. Some curious cats want to take a look at what you are doing and there’s a risk they will jump into the fish tank when you are occupied with other things.

Train or distract the cat

Another way of preventing the cat from interacting with the fish is to train it not to. Cats can learn tricks. My sister was able to teach her cat to shake her hand, so why not teach the cat to not interact with the fish tank?

You could also be sure to distract your cat by playing with it and keep a lot of toys around it. That way you remove the attention from the fish tank to the toys.


It should be possible to keep fish and cat together. You should only be sure that the cat and fish are not able to get to each other.

Do so by preventing the cat to get to the fish tank altogether and especially when doing a water change. That’s when the cat could take its chance to explore the tank and it might fall in.

These things go for all types of animals that you might have together with your fish tank. Dogs, birds, cats, guinea pigs, you name it!

Just be sure no animal gets stressed whether it’s your fish or your other animals and you can keep any pet together with your fish tank.

Some pets just need a little more attention from your part (like a cat) than others (like turtles) to prevent any accidents.

Related questions

Will my cat kill my fish? Your cat will kill and possibly eat your fish. Be sure to prevent it by having a lid on the fish tank. Also, be sure to prevent the cat from getting to the fish.

What happens if my cat eats a fish? Call your veterinarian. The fish could bring infections or parasites to your cat. Most likely your cat will be fine, but it’s better to be sure and get your cat checked.


I have been a fish keeper a big part of my life. During the years I have gathered and searched a lot of information about fish keeping and here, on the website, is where I share that information to help you with your fish keeping. I want to provide the information that I didn't get when I had a question about my fish tank.

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