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Can Cats Drink Tuna Water? Vet-Approved Nutritional Facts

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By Nicole Cosgrove

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Reviewed & Fact-Checked By

Dr. Amanda Charles

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The information is current and up-to-date in accordance with the latest veterinarian research.

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Many cats love fish and tuna is one of their favorites. The water that tuna is canned in is often safe for cats. That said, it shouldn’t become a big part of your cat’s diet, and you need to make sure there are no additional ingredients in the water. As a one-off treat, though, tuna water can help your cat stay hydrated and can encourage them to eat if added to their food.

Giving your cat the right kind of tuna water and making sure you don’t give them too much is important for your cat’s health. We explore the pros and cons in this article.

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Can Cats Drink Tuna Water?

There are a few things to keep in mind if you give tuna water to your cat. Tinned tuna can be packaged in fresh/spring water, brine (salt water), or oil. Tuna water from tuna packed in brine should never be fed to cats. The high salt content can cause serious electrolyte imbalances in a cat’s body. Oil is also too rich for most cats and should generally be avoided.

Provided that it is just tuna and water with no other ingredients, it’s usually safe for cats. However, you have to make sure you don’t give it to your cat excessively.

While it can be a useful way to encourage your cat to drink more, it’s never a good idea to rely solely on tuna water. As with all treats that you give your cat, tuna water is best in moderation.

canned tuna open can with fresh herbs garlic and lemon ingredients for preservs top view
Image Credit: Ilia Nesolenyi, Shutterstock

What Are the Benefits of Tuna Water for Cats?

Although there are a few risks associated with tuna water, there are some benefits too. When the tuna water contains no dangerous ingredients it can be used as an occasional healthy treat.

1. Hydration

Making sure your cat drinks enough can be a challenge simply because cats are incredibly fussy about where and what they drink. They can dislike having their water dish near their food bowl, litter tray, or in a heavy traffic area, and they might not be happy sharing with another pet. Many cats also dislike drinking standing water.

Cats will drink little and often throughout the day rather than gulp down a large amount of water all at once like dogs do. However, this habit can make it difficult to know when your cat is drinking and whether they’re drinking enough. Tuna water, either on its own or diluted into a water bowl,  can be a good way to make sure your cat does drink something, especially if it’s hot outside or they’re feeling sick, and you want to make sure they’re hydrated.

It isn’t a permanent solution, however. While it can help convince your stubborn feline to drink something, it should never be the only thing that your cat drinks. Use it as a rare treat, and consider other ways of encouraging your cat to drink more water, such as using a water fountain or moving the water dish to a quieter spot in the house.

cat drinking from a bowl of red bowl
Image Credit: fantom_rd, Shutterstock

2. Omega Oils

Tuna does contain a reasonable amount of omega 3 essential fatty acids and some of these may also be present in the tuna water. Omega oils help support your cat’s skin and coat health and can have anti- inflammatory properties but cats will only get small amounts from tuna water.

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What Are the Risks of Tuna Water for Cats?

It can be tempting to give your cat a large amount of tuna water to take advantage of the benefits. Unfortunately, tuna water is only beneficial if it’s used carefully as an addition to an already balanced diet.

1. Ingredients

Tuna water might sound like a simple treat for your cat, but not every can of tuna contains just fish and water. Sometimes, it can contain additional flavors and ingredients in an attempt to make the tuna more interesting for human consumers.

The tuna might be flavored with lemon or other toxic or artificial additives that are dangerous to cats. As mentioned above it can also use oil or brine instead of fresh water. While some oils, such as sunflower oil, are safe in small doses, others might not be.

You’ll need to check the label and make sure the can only contains tuna and water before giving your cat any. This way, the tuna water will be as safe as possible.

Canned tuna in a porcelain plate and on the kitchen counter
Image Credit: NMTD MEDIA, Shutterstock

2. Mercury

Fish and other marine life absorb mercury from their environment. Tuna is one of the many fish that have caused mercury poisoning in humans and cats when too much of it is eaten. Although the problem isn’t as common as it used to be due to the decline in mercury-based products and tuna water fed as an occasional addition to the diet is unlikely to lead to toxic levels of mercury.

3. Dietary intolerances

As with any new addition or change to your pets diet, tuna water may be unsuitable for some cats. If you are concerned your cat is suffering from any adverse effects after adding tuna water to their diet such as gastrointestinal upset then avoid feeding it and contact your vet for advice if the signs persist.

sad white cat
Image Credit: JumpStory

4. Addiction

Many cats love tuna and would quite happily eat a whole can for breakfast, lunch, and dinner. Unfortunately, this not only interferes with a balanced diet, but it can also result in your cat becoming addicted to tuna.

If this happens, they might refuse to eat anything but a can of their favorite fish. They’ll hear a can being opened or smell the fish from another room and rush in to beg for a bite.

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How to Serve Tuna Water to Your Cat

Tuna water is a simple treat to give your cat. It can be added to their food to entice them to eat it, mixed with water to encourage them to drink or as a special one-off. You can also pour a small amount into your cat’s food bowl without adding anything to it. Make sure you don’t give them too much, and never do it every day. Whether you add it to their meal or serve it on its own, your cat is sure to love every sip.



Cats can drink tuna water, provided that there are no additional ingredients beyond the tuna and the spring water, and that it’s served as a special treat. Tuna water can be added occasionally to your cat’s food as the aroma can stimulate and encourage their appetite. It can also be added to water to encourage drinking or given on its own. Most cats greatly enjoy the taste of tuna water but if given too often can start turning their nose up at other foods.

Featured Image Credit: OoddySmile Studio, Shutterstock

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