Can Cats Eat Tuna?

Cats famously love tuna, and a small amount as an occasional treat is fine. The problems arise when tuna becomes a regular part of the diet or the primary food source.

Mercury is the biggest concern with regular tuna feeding. Tuna is a large predatory fish that accumulates mercury through the food chain. Cats are small animals, so toxic levels build up faster than in humans. Chronic mercury exposure causes neurological problems: loss of coordination, muscle weakness, and vision changes.

Nutritional deficiency is the second major risk. Tuna alone does not provide a complete feline diet. It lacks adequate vitamin E, and a diet heavy in tuna can lead to steatitis (yellow fat disease), a painful inflammatory condition. Canned tuna for humans also doesn't contain added taurine — an essential amino acid cats cannot produce. Taurine deficiency causes dilated cardiomyopathy (heart failure) and retinal degeneration (blindness).

"Tuna addiction" is a real veterinary concern. Some cats who are fed tuna regularly refuse all other foods. This can become a serious problem if the cat develops a health condition requiring a special diet.

If giving tuna as a treat: use tuna packed in water (not oil), plain (no salt or seasonings), and limit to a tablespoon-sized portion once or twice per week at most. Cat-specific tuna treats are a better option as they're formulated with added taurine and nutrients.