Can Cats Eat Tuna?

Why Cats Are Attracted to Tuna

Tuna has an extremely strong smell and taste that most cats find irresistible. This is partly because tuna has a very high concentration of amino acids — including histidine and inosine monophosphate — that strongly activate feline taste receptors. Cats are obligate carnivores and are exquisitely sensitive to the flavour of animal proteins; tuna activates these receptors intensely.

The problem is that this strong preference can quickly become an obsession. Cats that are fed tuna regularly may begin to refuse their balanced commercial cat food in preference for tuna — a phenomenon sometimes called 'tuna addiction'. This is not merely a behavioural problem: a cat that refuses its balanced diet and eats only tuna will rapidly develop nutritional deficiencies, as tuna alone does not provide the full range of nutrients cats require.

The Risks of Feeding Tuna to Cats Regularly

Mercury accumulation is a significant concern with regular tuna consumption. Tuna — particularly larger species like albacore and yellowfin — accumulates methylmercury through the food chain (bioaccumulation). Cats that eat tuna frequently are at risk of mercury toxicity, which can cause neurological damage, tremors, and loss of coordination.

Thiamine (vitamin B1) deficiency can occur from feeding raw tuna, as raw fish contains an enzyme called thiaminase that destroys thiamine. Cooked tuna destroys thiaminase, making cooked tuna safer in this respect — but canned tuna intended for human consumption is typically cooked. However, the canning process and the salt content of human-grade canned tuna introduce separate concerns for cats.

Steatitis (yellow fat disease) is caused by a diet excessively high in unsaturated fatty acids (like those in tuna) combined with insufficient vitamin E. It causes painful inflammation of body fat, and in severe cases is life-threatening. It was historically common in cats fed primarily on tuna-based diets.

How to Offer Tuna Safely

If you choose to give your cat tuna as an occasional treat, opt for canned tuna in spring water rather than brine or oil. Brine tuna is very high in salt, which can stress the kidneys. Oil-based tuna adds excess calories and unnecessary fat. Drain the liquid thoroughly before offering a small amount.

A small piece of tuna — roughly a teaspoon — offered once a week or less is an appropriate treat-level amount for most adult cats. Never make tuna the basis of your cat's diet. Always ensure your cat's primary nutrition comes from a complete, balanced commercial cat food formulated to meet FEDIAF or AAFCO standards.

Tuna designed specifically for cats (in commercial cat food or cat-specific tuna treats) is formulated with appropriate nutrient balance and is generally safer than human-grade canned tuna offered regularly. Always check that any commercial cat food containing tuna is complete and balanced rather than a complementary food.

Signs of Tuna-Related Health Problems in Cats

Signs of thiamine deficiency include loss of appetite, neurological symptoms (circling, falling, seizures), dilated pupils, and an inability to hold the head upright. These signs are serious and require immediate veterinary attention.

Signs of mercury toxicity may include tremors, loss of coordination, abnormal gait, and progressive neurological deterioration. These develop with prolonged, frequent tuna exposure.

Steatitis may present as pain when touched (particularly around the abdomen and flanks), reluctance to move, fever, and loss of appetite. The fat deposits under the skin may feel abnormally firm or lumpy to the touch.

If your cat is eating tuna regularly and shows any of these signs, contact your vet promptly and inform them of your cat's diet.

Better Protein Alternatives for Cats

If you want to offer your cat a high-protein treat that is safer for regular use, there are better alternatives to tuna. Plain cooked chicken breast (no skin, bones, or seasoning) is an excellent choice — lean, protein-rich, and low in mercury. Plain cooked white fish such as cod or haddock is a safer fish option than tuna. Cooked salmon (plain, boneless) provides omega-3 fatty acids without the mercury concerns of large tuna species. Cooked prawn (without shell) is safe in small amounts and usually very popular with cats.

Always ensure any fish or meat offered is fully cooked to reduce the risk of bacterial contamination (Salmonella, Listeria) and to destroy any thiaminase present in raw fish. Never season food intended for your cat — no salt, garlic, onion, or any spices.