Why
Tuna are large predatory fish that accumulate relatively high mercury, which can build up with frequent feeding. Many canned tunas are packed in oil and salted, which can cause stomach upset, pancreatitis risk and excess sodium. Tuna alone isn't nutritionally complete, and cats can get so hooked they refuse their regular food.
How to give it / if eaten
Choose tuna packed in water with no added salt, or drain and rinse oil-packed tuna, and give only a spoonful once or twice a week, keeping treats under 10% of daily calories. Skip flavored or spicy tuna.
Watch for these signs
Oily tuna commonly causes diarrhea or vomiting. Long-term frequent feeding can lead to mercury-related signs such as wobbling and poor coordination, and cats may start refusing their food.
FAQ
Can I give my cat the tuna I eat?
A spoonful of plain tuna, drained and rinsed, now and then is fine. Avoid spicy tuna or tuna mixed with mayonnaise.
Can tuna be a daily treat for my cat?
Not daily: mercury can build up and picky eating often follows. Limit it to once or twice a week, or use cat-formulated tuna treats.
General information only. Weight, age and health conditions change how a pet reacts, so ask your vet if you are worried.