Cats are obligate carnivores and so require a regular source of protein in their diets. Most of us are (hopefully!) feeding our cats on a balanced and nutritionally complete diet appropriate for their life-stage; be it a kitten, junior, adult or senior cat. But can tuna be fed to cats as well? In this article we will take a look at the safest way to feed your cat tuna, should you so desire to do so.

Types of Tuna

Tuna comes in a variety of forms. Fresh (from the fish counter), or more widely available, in tinned form. Tinned tuna will be packaged in either in fresh water, brine (salt water) or oil. 

Certainly, these latter two forms of tuna are advised NOT to be fed to cats. The high sodium content in brine can cause serious electrolyte (salt) imbalances in the cat’s body and brain, potentially even reaching toxic levels. Such a severe imbalance will manifest as neurological symptoms. Additionally, oil may be too rich for many cats to digest, causing stomach upsets. 

So, the safest option remains to either feed your cat fresh tuna or, of that which is sold in tins, packed only in fresh water.

Nutrients in tuna

Tuna is a good source of protein. As a food source, it also contains a low carbohydrate content. Such elements of cat nutrition have gained an increased level of interest and popularity over the last decade. Low carbohydrate, high protein foods are thought to mimic a more natural feeding style for cats and therefore be associated with less obesity (and its related problems such as diabetes, heart disease and osteoarthritis). Tuna also contains a good amount of omega 3 essential fatty acids (EFA’s), which have been promoted as having anti-inflammatory properties.

Raw or cooked?

Something of a hotly contested debate at present is whether cats (and dogs) should be fed on raw food. There are arguments both for and against, with vocal advocates sitting on either side of the fence! Ultimately, the choice of whether to feed your cat raw or cooked tuna, is yours. Certainly, the potential for bacterial contamination of raw food is greater and this should probably be avoided if cats (or human household members), are immunocompromised, very young or very old, pregnant or lactating. 

If you choose to cook the tuna ahead of feeding it to your cat, remember to ensure that you do not add any seasonings or salt.

Also, be aware that a cat should never be fed an uncooked fish diet. Such a diet will lead to thiamine (vitamin B1) deficiency and (potentially severe) brain damage. A diet formed exclusively of fish, may also increase the risk of mercury poisoning. Caused by traces of this heavy metal that may be found within the fish’s body.


Personally speaking (and with my “save the planet” Greta-style hat on), I would also always try to ensure that I am purchasing a product that contains tuna which has been caught in a sustainable fashion. For tuna, this requires the Blue Tick “MSC mark” kitemark. This guarantees that the tuna has fished in a manner approved by the Marine Stewardship Council. In choosing such a product, you are helping preserve delicate marine ecosystems, prevent overfishing and avoid the associated damage to the seafloor. 

How much tuna is “too much?”

With a strong delicious smell and an enjoyable flavour, most cats will enjoy eating tuna. However, offer too much tuna to your cat and you may be making a rod for your own back! Some cats, if regularly offered tuna, may prefer its taste so much, that they then begin to turn their nose up at their regular foods. They can become picky eaters or may inconsistently eat their main source of food. They may also gain weight. 

In an ideal world, only 10% of a cat’s daily intake of calories would come from tuna. The remaining 90% and thus the bulk of the diet, would be their complete and balanced, appropriate life-stage food. 

And how else can tuna be fed?

An alternative approach would be to buy a commercial cat food that contains a high percentage of meat/protein within it; and tuna as the main component of the protein. This is an approach I like to take with my own cats. They get to enjoy a high meat/fish content food, yet I also rest assured that they are simultaneously receiving all the balanced nutrition they need in the form of vitamins and minerals. I feel this more naturally meets their dietary needs. Occasionally, a couple of times a month, my boys have a treat and share a small can of tuna in fresh water, between them. This has been aptly named “Feline Fish Friday” by my children!

Does tuna have a role in increasing palatability of foods?

Tuna can also be used (along with other fish / meats / products), as a “topper” to increase the palatability of other foods. It may be sufficiently aromatic, to stimulate and encourage an appetite, in an otherwise inappetant cat.

Be aware of the phenomenon of “food aversion” however. This is when a cat (unbeknown to us), feels nauseous, and is inadvertently offered a specific type of food at the same time. Given the feeling of sickness that cat is experiencing, it will refuse the food. Furthermore, in the future, the cat will also have learnt to associate that particular type of food with the sensation of nausea; thus developing a potentially long-term, food aversion.

And finally…

Like any food type, tuna may be unsuitable for certain individual cats. Such a dietary intolerance may result in allergic symptoms. These may involve the skin (itchy, red, flaky or bald skin with small bumps) or the intestinal tract (inappetence, vomiting, diarrhoea and flatulence). If you feel that your cat is suffering from such symptoms having consumed tuna, please stop feeding it immediately and contact your Vet for advice.

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