How much tuna for your cat?
Most guides say "a few pieces". Enter your cat's weight and get the actual daily ceiling, worked out from tuna's calories and the 10%-of-daily-calories treat rule vets use.
Assumes a healthy, neutered adult at a stable weight, and that this is their only treat that day. Puppies, pregnant, very active or unwell pets need different amounts — ask your vet.
Why this verdict for cats
Cats love tuna, but a tuna-only diet causes nutrition problems and mercury build-up.
A little cooked or water-packed canned tuna is a fine occasional treat — and famously beloved by cats. The problem is the habit: tuna every day is where the risks live.
How much is safe?
A small spoonful of plain tuna canned in water (not oil, not salted) or a bite of cooked fresh tuna, occasionally. For cats especially, tuna should be a treat — not a meal replacement.
What happens if a cat eats too much?
Tuna is higher in mercury than smaller fish, so a steady tuna habit builds exposure over time. In cats, a tuna-heavy diet is also nutritionally unbalanced and can cause health problems — and some cats get so hooked they refuse normal food.
How to serve it safely
Offer plain tuna in water, drained, as an occasional treat or food topper. Skip tuna in oil, salted tuna, and anything seasoned.
🍽️ Feeding it safely?
Frequently asked questions
Can cats eat tuna every day?
No — daily tuna risks mercury build-up and an unbalanced diet, and can turn cats into stubborn tuna-only eaters. Keep it occasional.
Is canned tuna in oil ok?
Water-packed is the right choice — oil adds unnecessary fat, and salted versions add sodium.
Can pets eat raw tuna (sushi-grade)?
Best not — raw fish carries parasite risk and an enzyme that breaks down vitamin B1. Cooked is safer.
More meats & proteins for cats
By the CanMyPet Editorial Team · Reviewed against ASPCA Animal Poison Control, the American Kennel Club (AKC) and Pet Poison Helpline · Last updated July 31, 2026.
Sources
- ASPCA — People Foods to Avoid Feeding Your Pets
- American Kennel Club — Dog Nutrition
- Pet Poison Helpline — Poison List