Can cats eat tuna?

Is tuna safe for cats?

Plain tuna in water is safe as an occasional treat, but tuna is not a complete food for a cat. Canned tuna meant for humans should not make up the diet, and Cornell's Feline Health Center notes that some cats fed canned fish products meant for humans developed potentially serious neurological disorders.

A cat can have a little now and then; the sections below cover what the sources say goes wrong when it becomes a habit.

How much tuna can I give my cat?

There is no tablespoon-per-week rule in the sources behind this page. The portion in the card above is the practical guide: a small spoonful of plain canned tuna in water, given only occasionally, and not as a replacement for a balanced cat food.

What the sources do describe is what happens when tuna is fed as a dietary staple, which the next sections cover.

Can cats eat tuna every day?

No. Merck records vitamin E deficiency, leading to pansteatitis or yellow fat disease, in cats given large quantities of canned tuna, and the guidance is that tuna should be an occasional treat, not a dietary staple. The risk comes from repeated, frequent feeding rather than a single serving.

The signs to watch for in a cat on a canned-tuna-heavy diet are loss of appetite, listlessness and a belly that is painful to touch. It is a disease of quantity and duration: it is described in cats eating a great deal of tuna over time, not in cats given a taste.

Can cats eat tuna in oil, brine or with sauce?

No. Offer only tuna packed in water, with no oil or seasoning, as the guidance above says. Onion and garlic, in any form including powder, are toxic to cats, so check the ingredient list of any flavored or seasoned can before it goes anywhere near your cat's bowl.

See why onion is toxic to cats for what a small amount can do. Tuna mixed into a dressing or a sauce is not plain tuna.

What if I have run out of cat food and only have tuna?

One meal of plain tuna in water is not what the veterinary sources warn about: the documented problems develop over a sustained, fish-heavy diet. Get your cat back onto a complete cat food as soon as you can, because canned tuna made for people is not a complete food.

For anything else in the cupboard, the full list of foods shows which are rated safe and the sources behind each rating.

Is raw tuna safe for cats?

Not as a regular food. Some raw fish contain thiaminase, an enzyme that destroys thiamine; Merck names raw freshwater fish and clams and does not say whether raw tuna does. Thiamine deficiency has been documented in animals fed diets made up mostly of raw fish. Cooking destroys thiaminases, and so does the heat of canning.

That is why the often-repeated claim that canned tuna destroys thiamine mixes up two different products. In cats, thiamine deficiency shows up as loss of balance, head tremors or seizures.

Is tuna bad for cats because of mercury?

The sources do not single tuna out. Merck notes that commercial fish-based dietary products have been associated with chronic mercury toxicosis in cats, and that mercury accumulates up the food chain to its highest levels in top predators such as sharks, king mackerel and tilefish. It gives no figure for tuna.

What the source supports is an association with fish-based diets, which is one more reason to keep tuna an occasional treat.