Can Cats Eat Tuna? Canned, Raw and How Often
Few foods trigger a cat's enthusiasm like the sound of a tuna can being opened. It is no wonder people ask whether tuna is good for cats. The honest answer is that a little is fine, a lot is not, and the way it is served makes a difference.
What tuna offers
Tuna is a lean, protein-rich fish that smells strongly, which appeals to a cat's powerful sense of smell. It provides omega-3 fatty acids, selenium and B vitamins. These are good things, but they do not make tuna a complete food for a carnivore. Cats need balanced taurine, calcium, vitamin E and many other nutrients that tuna alone does not provide.
Problems with too much tuna
Nutritional imbalance. A diet heavy in tuna meant for people lacks sufficient vitamin E relative to the amount of unsaturated fat. Over time this can cause a painful inflammation of body fat called steatitis, sometimes called "yellow fat disease." Tuna also lacks sufficient calcium, so a cat living mostly on tuna can develop skeletal problems.
Mercury. Tuna is a large, long-lived predator that accumulates mercury. A small amount occasionally is not a worry, but regular feeding raises the risk of chronic exposure. Light tuna generally contains less mercury than albacore or bigeye tuna.
Addiction to flavor. Cats can become so devoted to the strong flavor that they refuse their regular food. A cat that holds out for tuna and skips meals risks a dangerous drop in food intake, and fasting for more than a day can cause hepatic lipidosis, a serious liver condition. See our emergency warning signs guide for when a cat's appetite change becomes urgent.
Sodium. Canned tuna can contain a lot of salt, which is hard on cats with kidney or heart disease.
How to serve tuna safely
- Choose canned tuna in water with no added salt. Avoid oil, brine and flavored varieties such as lemon pepper or those with garlic and onion.
- Use a small amount. A teaspoon or two of flaked tuna is a generous treat for most cats.
- Serve occasionally. Once a week at most is a common suggestion, and less is fine.
- Mix with regular food. A small amount on top of a complete meal helps a picky cat accept it without replacing the diet.
- Refrigerate leftovers in a covered container and use within a day or two.
Our cat food amount calculator helps you account for treat calories.
What about tuna made for cats?
Commercial tuna-flavored cat foods are formulated to be complete and balanced, so they are different from tuna meant for people. Cat tuna treats are usually meant as treats rather than a main meal. Check the label for "complete and balanced" wording if you want to use a product as the main diet.
Raw tuna
Raw fish can carry parasites and bacteria, and some species contain thiaminase, an enzyme that breaks down thiamine. Cooking or buying products prepared for pets reduces risk. For more on raw feeding, read can cats eat raw meat.
Better fish choices
Plain cooked salmon offers more omega-3 and typically less mercury. Cooked shrimp can be an occasional alternative. Whatever you choose, remove bones and keep portions small.
Quick reference
| Question | Answer |
|---|---|
| Safe form | Canned in water, no added salt, flaked in tiny amounts |
| Rough calories | About 1 calorie per gram for light tuna in water |
| Sensible treat size | One or two teaspoons |
| Frequency | Rare, not daily |
| Avoid | Tuna in oil, flavored tuna, raw tuna, tuna as a main meal |
If your cat only wants tuna
A cat that refuses its regular food in favor of tuna has been trained, by repetition, to hold out. To reset the habit, stop offering tuna, serve a measured portion of the regular food at set times and pick it up after about twenty minutes. Do not let your cat go without eating for more than a day, because cats are prone to a liver condition after fasting. If your cat will not eat anything for 24 hours, call your vet. A gradual approach, mixing a tiny amount of a new food into the old one, often works better than an abrupt change.
Tuna for medication and appetite
Some vets suggest a little tuna juice to help a cat take a pill or to tempt a sick cat to eat. This is fine as a short-term tactic when approved by your vet, but it should not become a daily habit. If appetite loss lasts more than a day, the underlying cause matters far more than the flavor, so book a visit rather than relying on stronger smells.
When to see a vet
If your cat will only eat tuna, loses weight, vomits repeatedly or shows lethargy, see a veterinarian. Selective eating can signal dental pain or illness. For more guidance on other foods, use the free cat food and plant safety checker.
Frequently asked questions
Can cats eat tuna every day?
It is not a good idea. Daily tuna can lead to nutritional imbalance, mercury exposure and a cat that refuses regular food.
Is tuna in water or oil better for cats?
Water-packed tuna with no added salt is better. Oil adds fat, and flavored varieties can contain onion, garlic or too much sodium.
Can cats drink tuna water?
A small spoonful of the water from plain tuna is fine as a rare treat, but it can be salty, so choose unsalted varieties.
Is raw tuna safe for cats?
Raw fish can carry parasites and bacteria, so cook it first, or use specially prepared products designed for cats.
Sources and further reading
Pet food rules and nutrient standards come from regulators and professional bodies. Start here when you want the primary source.
- ASPCA: people foods to avoid feeding your petsWhich common kitchen foods are unsafe for dogs and cats.
- ASPCA Animal Poison Control CenterToxic plants and foods lists, plus a 24-hour helpline.
- Pet Poison Helpline24-hour poison advice staffed by veterinary toxicologists.
Tailwisp is independent and written under our editorial policy. Learn who we are, or browse all cat guides.
This article is general educational information, not veterinary advice. Every cat is different. If your cat is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.