Quick answer: Cats can eat a small amount of plain tuna as an occasional treat, but human tuna is not complete cat nutrition. PetMD suggests no more than about 1 tablespoon of plain, cooked tuna once a week, and Tufts advises avoiding albacore and keeping tuna to under 10 percent of daily calories. Some vets advise skipping it entirely, so check with yours.
Few foods make a cat appear faster than the sound of a can opener. Tuna smells irresistible to cats, and many owners wonder whether it is a harmless treat or a hidden health risk. The honest answer sits in the middle: a spoonful now and then is considered acceptable by some veterinary sources, while regular tuna can cause real nutritional problems. Here is what the experts say, how much is reasonable and what to give your cat instead.
Is tuna safe for cats?
In small amounts, plain tuna is generally considered safe. PetMD describes tuna as high in protein, low in carbohydrates and rich in omega fatty acids, as long as it is cooked, completely plain and given in a small quantity. However, opinions among veterinary sources differ. A VCA Animal Hospitals resource advises against feeding tuna to cats at all, pointing out that tuna meant for people lacks essential nutrients and is not supplemented with vitamin E or other antioxidants. Because of that disagreement, treat tuna as an optional extra, never a staple, and ask your vet whether it suits your cat.
Why too much tuna is a problem
Nutritional imbalance
Human-grade tuna is not formulated to meet a cat’s needs. PetMD notes it is deficient in vitamin E, and PetMD’s list of dangerous foods warns that regular feeding can cause steatitis, a painful inflammation of body fat, because tuna is high in unsaturated fatty acids but low in antioxidants. PetMD’s nutrition blog also notes that canned tuna made for people does not have thiamine added, so a diet heavy in tuna can contribute to thiamine deficiency.
Mercury
Tuna is a large fish, and larger fish tend to carry more mercury. PetMD says albacore has particularly high levels. A veterinarian writing for Tufts Now says mercury poisoning in cats is hard to spot because the signs, such as loss of coordination and balance, can mimic other illnesses, and recommends only occasional treats of canned chunk-light tuna, not albacore, adding no more than 10 percent of daily calories.
Extra calories and weight gain
Tuna is calorie dense, so a few extra forkfuls can quickly add up, particularly for a small indoor cat. PetMD cautions that too much can lead to obesity rather quickly. If your cat is already carrying extra weight, our vet-guided weight loss plan explains how to cut treats without a fight.
Fish allergies and habit forming
Some cats are allergic to fish, and cats who get tuna regularly can become picky about their regular meals, which makes it harder to feed a balanced diet. Cats are also quick to learn that begging works.
How much tuna can a cat have?
PetMD’s guidance is no more than 1 tablespoon of plain, unseasoned, cooked human-grade tuna, once a week. Tufts suggests keeping rare indulgences below 10 percent of daily calories. Because treats should be a small share of the diet no matter what they are, our guide to how much to feed your cat is a helpful companion for working out portions. Remember that VCA recommends skipping tuna altogether, so the safest course is to ask your own veterinarian.
Which types of tuna are better or worse?
| Type of tuna | Verdict | Notes |
|---|---|---|
| Plain canned chunk-light tuna in water | Occasional treat at most | Tufts advises chunk-light over albacore and a strict calorie cap |
| Albacore (white) tuna | Avoid | PetMD and Tufts both flag higher mercury levels |
| Tuna packed in oil, brine or with flavorings | Avoid | Added oil, salt and seasonings are not suitable for cats |
| Raw tuna | Avoid | PetMD advises cooking tuna and serving it plain |
| Commercial cat food containing tuna | Generally fine | PetMD notes these foods are formulated to be complete and balanced |
| Tuna for kittens | Avoid | PetMD says wait until at least one year old |
How to offer tuna safely (if you decide to)
- Choose plain tuna. Water-packed, no added salt, no spices, no garlic or onion. The ASPCA lists onions, garlic and chives among foods to avoid, so check any flavored product carefully.
- Drain it well and cut it into tiny pieces.
- Keep the portion small. A teaspoon or two as a topper on regular food is plenty.
- Make it occasional, not a routine. Cats can learn to refuse other food in favor of tuna.
- Watch for reactions. Stop and call your vet if you see vomiting, diarrhea, itching or lethargy.
Better ways to treat a tuna-obsessed cat
If it is the smell and excitement your cat loves, you can recreate that without the nutritional downsides.
- Use a tuna-flavored cat food or treat that is made to be complete and balanced, in small amounts.
- Turn dinner into a hunt. Hide part of the regular meal in a puzzle feeder or tuck kibble around the room so your cat has to search. Our indoor cat enrichment ideas include several food-based games.
- Offer play instead of food. A wand toy session before dinner burns calories and satisfies the urge to hunt. A pop-up space like the Pop-Up Portable Cat Play Tent gives your cat a hiding and pouncing spot to keep things interesting.
- Stick to a feeding routine. The right balance of wet and dry food matters more than treats; see wet vs dry cat food for a simple comparison.
When to call the vet
Contact your veterinarian if your cat eats a large amount of tuna, especially seasoned or oil-packed tuna, or if you notice vomiting, diarrhea, weakness, wobbliness or difficulty walking. Long-term tuna feeding that shows up as stiffness, pain when touched or poor coat quality is also worth a conversation. If you suspect your cat ate something harmful, the ASPCA and PetMD both advise calling your vet or an animal poison hotline.
Make mealtime and playtime more exciting
Skip the tuna habit with more play. The CozeCats Pop-Up Portable Cat Play Tent gives indoor cats a fun place to hide, pounce and burn off energy.
Frequently asked questions
Can cats eat canned tuna?
Plain canned tuna in water is considered an occasional treat by some sources, but it should never replace a complete cat food. Avoid tuna packed in oil or brine and anything with added flavorings.
Can cats eat tuna every day?
No. Daily tuna can lead to nutritional imbalances such as vitamin E and thiamine problems, and adds mercury and calories. Tuna-based commercial cat food is formulated to be balanced and is a different matter.
Is tuna bad for kittens?
PetMD advises not offering tuna to kittens until they are at least one year old, because they are more sensitive to diet imbalances and toxins.
Why do cats love tuna so much?
Tuna has a strong smell and rich flavor that cats find very appealing. That enthusiasm is exactly why it is easy to overfeed.
What should I feed instead of tuna?
Use complete and balanced cat food, with small amounts of treats made for cats. Foraging puzzles and play can make meals feel special without extra human food.
Can cats eat tuna in oil or with seasoning?
No. Oils, salt and seasonings are not suitable for cats, and the ASPCA lists onions and garlic as foods to avoid.
Keep reading
- Wet vs dry cat food: which is better?
- How much should I feed my cat?
- Can cats drink milk?
- How to help your cat lose weight safely
Sources
- PetMD: Can Cats Eat Tuna?
- PetMD: Dangerous Foods for Cats
- VCA Animal Hospitals: Milk and Tuna for Cats
- Tufts Now: Canned tuna and mercury in cats
- ASPCA: People Foods to Avoid Feeding Your Pets
This article is general information, not veterinary advice. If you are worried about your cat’s health, contact your veterinarian.
