Cats can have a small amount of plain cooked tuna as an occasional treat, but tuna should not replace a complete and balanced commercial cat diet. Tuna from a can meant for humans is often high in sodium and may be packed in oil or flavored broths that are not ideal for cats. Feeding tuna too often can lead to nutritional imbalance because tuna alone does not provide all the vitamins, minerals, and amino acids cats need, including adequate taurine in the right balance with other nutrients.

A separate concern is mercury. Larger predatory fish, including some tuna species, can accumulate mercury. Regular or heavy feeding increases the risk over time. Kittens, pregnant cats, and cats with existing health issues are especially important to keep on veterinarian-approved diets rather than fish-heavy home routines.

If you offer tuna, choose water-packed tuna without added salt when possible, drain it well, and keep portions tiny. Watch for digestive upset or allergic signs such as vomiting, diarrhea, or itching. Cats with known fish allergies should avoid tuna entirely.

For everyday meals, use food labeled complete and balanced for cats. If you want fish flavor, select a reputable cat food that meets Association of American Feed Control Officials (AAFCO) standards. Your veterinarian can help you choose wet versus dry options and portion sizes based on your cat’s age, weight, and health.