Can I Feed My Cat Tuna?

What to know about cats and this fishy treat 🐟

cat with cans of tuna

It’s a bit of a cliché that cats love tuna — so everytime you eat a tuna sandwich, you’ve probably been tempted to sneak your cat a bite (especially if you see him staring at you from under the table).

But you might have wondered if it’s actually OK to give him canned tuna. Can cats eat tuna fish safely?

The short answer is yes — but only in moderation, and there are some things you need to know first.

We spoke to LeeAnna Buis, a certified feline training and behavior consultant with Feline Behavior Solutions, to find out everything you need to know about feeding your cat tuna.

Is tuna good for cats?

Tuna can be a healthy snack for cats when given sparingly.

“[Tuna] can help stimulate kitty appetites and offers protein, omega-3 fatty acids, potassium and other important vitamins and minerals,” Buis told The Dodo.

Many cat foods actually contain tuna as an ingredient. The proteins, vitamins and minerals in tuna have a lot of benefits for cats, including improving eyesight, boosting their immune systems, giving them energy and contributing to skin and coat health.

However, that doesn’t mean tuna’s a perfect food.

Tuna has some health benefits, but there are downsides to giving your cat tuna, too — especially if you let him overindulge.

Tuna lacks nutrients and can be unhealthy

While tuna can be a nice treat in small amounts, it doesn’t have all the nutrients your cat needs and can be high in unsaturated fats, so it’s not a good staple food.

Canned tuna in particular can also have a lot of salt, Buis said, which can result in an electrolyte imbalance, causing its own set of health issues. Just like in people, an electrolyte imbalance can cause your cat’s cells to malfunction.

Tuna is also high in unsaturated fats. A diet high in unsaturated fats can lead to vitamin E deficiencies in cats.

“It does not supply all of the nutrients your cat needs,” Buis said. “Fed in large amounts, it … leaves your cat lacking important nutrients.”

Vitamin E deficiency can cause a disease called steatitis, or yellow fat disease, which is an inflammation of fatty tissue. Young cats and overweight cats are more predisposed to this condition, but any cat who has too much unsaturated fat in his diet can develop it (tuna-flavored cat food will not put your cat at risk because it usually includes a mix of different types of fish or meat to provide your cat with the balanced nutrients he needs). There are also other diseases associated with vitamin E deficiency in cats, but yellow fat disease is the most common.

This disease can be life-threatening, and while an occasional bite of tuna probably won’t cause your cat to develop it, it’s super important to make sure you feed your cat a balanced diet without a lot of unsaturated fats and to look out for the below symptoms if you’re feeding him tuna regularly.

Symptoms of steatitis or yellow fat disease include:

  • Fever
  • Dull coat
  • Sensitive skin
  • Lethargy
  • Loss of appetite
  • Masses under the skin
  • Signs of depression

If you notice any of these signs of yellow fat disease in your cat, you should contact your vet immediately.

Tuna contains mercury

Tuna also has higher mercury levels than many other types of fish, so feeding too much to your cat can be harmful and lead to mercury poisoning.

“It not only leaves your cat lacking important nutrients, but can also cause mercury poisoning, as mercury is toxic to cats,” Buis said.

While mercury poisoning is rare, it can be serious — symptoms of mercury poisoning include:

  • Loss of coordination
  • Loss of balance
  • Difficulty walking
  • Other neurological issues

Cats can have food allergies

While lots of cats love tuna, not all cats are able to eat fish — some cats can be allergic to it. So when you give your cat tuna for the first time, you should be on the lookout for any allergy symptoms.

Symptoms that your cat might be allergic to tuna include:

  • Itching
  • Rash
  • Hair loss
  • Digestive problems
  • Liver problems
  • Kidney problems
  • Pancreas problems
  • Conjunctivitis

If you think your cat might have a food allergy, make an appointment with your vet right away to confirm it (especially as these symptoms can all be signs of other problems).

Cats can become tuna-obsessed

As adorable as it is, sometimes cats can go a little too crazy for tuna — which can actually make your life more difficult.

“It’s also said that cats can easily become a bit obsessed with tuna, making it tough to reward them with other treats and keep them eating their primary cat food,” Buis said.

This can become a problem if your cat refuses to eat any food but tuna, since tuna doesn’t have all the nutrients he needs in a complete meal.

Can cats eat tuna out of the can?

If you want to give your cat tuna, canned tuna is actually better than raw fish.

“The canning process removes thiaminase, an enzyme found in raw tuna that destroys vitamin B1, which our cats need,” Buis said. “Look for canned tuna in spring water. Avoid brine, which is higher in sodium, and oil, which can cause digestive issues.”

As always, if you’re unsure about whether or not you should give your cat tuna, talk to your vet.

“If you’re considering tuna for your cat, it’s best to chat with your veterinarian about how much is too much and whether your cat has any health issues that may be exacerbated by this stinky treat, such as kidney and heart disease,” Buis said.

Tuna should only be given as an occasional treat, and it shouldn’t make up a significant chunk of your cat’s diet — a teaspoon every now and then is enough to satisfy your cat (but still check with your vet about how much is OK for him).

So while tuna shouldn’t be given as a full meal, as long as your cat doesn’t have any allergies, you can give him some canned tuna every now and then as a treat — just be prepared in case he becomes a little too obsessed!