How to Cat-Proof Your Fish Tank

This article is contributed by guest writer David Thomas, a lifelong fish keeper and expert.

Cats don’t have the same appreciation for beautiful fish in a diverse ecosystem that most fish keepers do, but that doesn’t mean they won’t be fully engrossed by your fish tank. There’s plenty of opportunity for cats to get up to some feline mischief with a fish tank, but just as much opportunity for owners to prevent it. The basic steps outlined below should be enough to keep your fish and your cat happy and healthy. 

Cover your fish tank

Maybe this should go without saying, but it also can’t really be said enough. Fitting a secure lid onto your fish tank is the number one thing you can do to protect your fish from your cat. For one thing, most obviously, it will prevent your cat from drinking from the tank or plucking your fish out like it’s a seafood restaurant. It will also protect your fish from jumping out of the tank, and your cat from jumping into it.

A well-crafted, well-fit glass or acrylic lid will also reduce the amounts of sounds and smells coming from the tank, which should reduce your cat’s interest in interacting with it in the first place. You can also fit a stretch of wire mesh over the top of the tank, if a proper lid isn’t available. This doesn’t solve the sound or smell issues, but it may be less comfortable for your cat to lay on, as they sometimes like to do.

If your cat does like to lay on top of your tank lid, it can stress out your fish, but stacking things on top of it, or a dedicated cat deterrent, as detailed below, should discourage your cat from setting up shop on top of the fish tank.

Place the tank somewhere the cat can’t easily watch it

A lot of people think letting their cat watch their fish tank is harmless, since it entertains the cat without seeming to upset your fish, but this behavior should actually be discouraged. It can stress out your fish if your cat watches from up close, but it also encourages your cat’s interest in the fish tank and may lead to them escalating to interference with the tank.

Placing your tank in such a way that it’s difficult for your cat to get to the right level to watch it, usually by moving or removing other furniture in the vicinity of the tank stand, will significantly decrease your cat’s interest in it. If you still need to entertain your cat, consider a cat tree, opening the windows, or even turning on the TV.

Discourage your cat from approaching or interacting with the tank

As mentioned above, even seemingly benign interactions between your cat and your fish tank can stress out your fish and lead to further problems with your cat and your tank. Luckily, there are a wide variety of deterrents available to discourage your cat from having anything to do with your fish tank. You can place electric scat mats, spiky cat deterrent mats, double sided tape, or aluminum foil on the tank lid, tank stand, and other nearby surfaces to keep the cat off of them.

Citrus scents, like lemon, orange, or grapefruit, are also unpleasant to cats and will keep them away. If your cat is intent on watching your fish tank regardless, you can cover it with a blanket or other cover when you aren’t home to block their view. When you are home, discourage this behavior with a spray bottle until they eventually stop altogether.

Tidy up any cords or covers hanging from the tank stand

Cats love to bat and tug at anything dangling over their head, from a piece of string to a tablecloth to an electrical cord. This is very cute until they tug your filter cord too hard and pull the entire fish tank down on top of them. Tidy away any electrical cords by taping them up or curling them up on the table so your cat can’t reach them. If you have a tablecloth or other cover on your tank stand, tape the edges to the bottom of the table so they don’t hang down. Consider getting your cat some interactive toys that will engage the same predatory instincts without endangering your fish.

Consider replacing your cat’s water bowl

This one may seem odd, but if your cat is mostly interested in drinking from the fish tank, a new water bowl might solve your problem. Obviously, chemicals and waste make it unsafe for your cat to drink from the tank; it will also stress out your fish quite a bit. However, cats have a natural fascination with running water; similar to humans, they have an evolutionary bias to think of it as cleaner and safer to drink than still or stagnant water.

If your tank has a pump or aerator that keeps the water moving, your cat might find that more appealing than a regular water bowl. A fountain water bowl, which keeps their water moving, might hold their attention better and help them stay hydrated without disturbing your fish or your fish tank.

In Summary

Despite their reputation as natural enemies, there’s no reason your cat can’t live in harmony with your fish tank. A few simple precautions are all you need to protect your fish from a cat-astrophe!