Can Cats Eat Tuna?

Can cats eat tuna? As a small extra, generally yes. WSAVA's guide to extras for cats lists plain canned tuna in water, and keeps all extras under 10% of a cat's daily calories.

As a meal, veterinary sources advise against it. Cornell's Feline Health Center notes that some cats fed canned fish meant for people have developed potentially serious neurological disorders.

The Merck Veterinary Manual links large amounts of canned tuna with vitamin E deficiency and a painful fat disease called pansteatitis. Below is what the sources say about the can, the amount, and why cats find tuna so hard to resist.

Why do cats love tuna so much?

A 2023 study in Chemical Senses found the answer in umami, the savory taste of meat. The researchers showed for the first time that cats carry the umami taste receptor, and they proposed that umami is the main taste that draws cats to food.

Tuna happens to be loaded with two compounds that switch that receptor on together: inosine monophosphate and free histidine. In the study's words, the pair produces "a strong umami taste synergy."

Can cats eat tuna as a meal?

Cornell's Feline Health Center advises against canned fish made for people as a cat's diet. It notes that some cats fed canned fish meant for humans have developed potentially serious neurological disorders.

The Merck Veterinary Manual gives a second reason. It states that "naturally occurring deficiencies of vitamin E have occurred in cats given large quantities of canned tuna, resulting in the development of pansteatitis (yellow fat disease)."

Merck lists the signs as loss of appetite, listlessness, tenderness when the belly is touched, and lumpy, discolored body fat. Vitamin E works as an antioxidant, and Merck explains that it helps keep the fats in cell membranes from breaking down.

Then there's thiamine (vitamin B1). Merck notes that thiaminases, enzymes that destroy thiamine, are found in raw freshwater fish and clams, and that cooking and canning destroy them.

In cats, Merck lists the signs of thiamine deficiency as loss of appetite, failure to grow, neurologic dysfunction, seizures and muscle weakness. It adds that the deficiency generally does not develop in cats fed properly prepared complete and balanced commercial diets.

That phrase, complete and balanced, is the key. Cornell explains that foods carrying the AAFCO statement are nutritionally complete for the life stage on the label.

Merck adds that a food that doesn't meet those standards must be labeled only as a treat or for occasional feeding.

That is the line Cornell and Merck draw between a tuna-flavored cat food labeled complete and balanced and a can of tuna made for people. Look on the label for the AAFCO statement.

Does the mercury in tuna matter for cats?

None of the veterinary bodies cited here sets a mercury limit for cats eating tuna, so the evidence is limited.

The FDA's fish advice for people sorts tuna by mercury. Canned light tuna, including skipjack, is a "best choice." Albacore (white) tuna is a "good choice." Bigeye tuna sits on the list to avoid.

Researchers at the University of Nevada, Reno have studied mercury in pet food.

Their 2021 study in Science of the Total Environment tested 127 cat and dog foods. Total mercury was above suggested maximum tolerable limits in three products, and methylmercury was at safe levels in all of them.

The same team has called mercury "a potent neurotoxin" and argued that pet foods should be tested for it independently. Ask your vet whether the type and amount of tuna you offer is a concern for your cat.

Tuna in water, oil or brine: which should I choose?

WSAVA's calorie guide for cats lists tuna canned in water, so the calorie figures below apply to that kind only. The sources point to reasons for caution with the others:

• Tuna in oil isn't covered by WSAVA's figure. Ask your vet before offering it.
• Tuna in brine is salty. The ASPCA warns that excessive salt intake can produce increased thirst and urination.
• Flavored tuna, such as tuna salad, sandwich fillings or seasoned pouches, can contain onion or garlic. Merck calls cats the species most susceptible to onion and garlic poisoning, especially from powdered and dried forms.

On raw tuna and sushi, the AVMA discourages feeding any raw animal protein to cats, fish included. Our guide to raw food for cats explains why.

Call your vet promptly if your cat:

• ate tuna salad, a sandwich filling or anything seasoned with onion or garlic
• got into salty tuna and is drinking or peeing much more than usual, which the ASPCA links to excess salt
• has been eating a lot of tuna and shows any of the pansteatitis signs Merck lists: loss of appetite, listlessness, or tenderness when her belly is touched
• shows any of the thiamine deficiency signs Merck lists, such as muscle weakness or seizures

For the full list of foods to keep off her plate, see our guide to what cats can eat.

How much tuna can a cat have?

WSAVA advises that everything outside a cat's main food stays under 10% of her daily calories. That covers every extra in the day, not only tuna.

WSAVA lists canned tuna in water at about 36 calories per ounce (28 g). The right-hand column below is our estimate, worked from those WSAVA figures; WSAVA does not publish gram amounts itself.

Cat's weight	Daily allowance for extras (WSAVA)	Tuna in water that uses it all (our estimate from WSAVA)
3 kg (6.6 lb)	20 calories	About 16 g
4 kg (8.8 lb)	22 calories	About 17 g
5 kg (11 lb)	25 calories	About 19 g
6 kg (13.2 lb)	26 calories	About 20 g

By that estimate, it is well under an ounce, and only on a day with no other extras.

The ASPCA is stricter, suggesting extras stay at 5% or less of a cat's daily food. By the same arithmetic, that would be about half the estimated amounts above. Your vet can set a figure for your own cat.

Our guide to cat food toppers covers adding extras to a complete diet.

Questions new cat parents ask

Can kittens eat tuna?

The ASPCA keeps all of a kitten's extras to 5% or less of daily intake, alongside a complete kitten food. Ask your vet before offering tuna to a kitten.

Is tuna cat food okay to feed every day?

Cornell explains that a food carrying the AAFCO statement is complete and balanced for the life stage on the label. Merck notes that a food that doesn't meet those standards must be labeled as a treat or for occasional feeding only.

Can cats eat tuna every day?

Cornell warns against canned fish made for people as a regular diet, and Merck links large quantities of canned tuna with pansteatitis. WSAVA keeps all extras under 10% of daily calories.

Can cats eat tuna in oil?

WSAVA's calorie guide lists tuna canned in water, not oil. Ask your vet before offering oil-packed tuna.

Sources

• Cornell Feline Health Center: Feeding Your Cat
• Merck Veterinary Manual: Nutritional Requirements of Small Animals
• Merck Veterinary Manual, Cat Owners: Proper Nutrition for Cats
• Merck Veterinary Manual: Garlic and Onion (Allium spp) Toxicosis in Animals
• WSAVA: Feeding Treats to Your Cat
• ASPCA Animal Poison Control: People Foods to Avoid Feeding Your Pets
• ASPCA: Cat Nutrition Tips
• FDA: Advice about Eating Fish
• AVMA policy: Raw Diets for Dogs and Cats
• Dunham-Cheatham SM, et al. Using a next-generation sequencing approach to DNA metabarcoding for identification of adulteration and potential sources of mercury in commercial cat and dog foods. Science of the Total Environment, 2021
• Dunham-Cheatham SM, et al. What is in commercial cat and dog food? The case for mercury and ingredient testing. Science of the Total Environment, 2019
• McGrane SJ, et al. Umami taste perception and preferences of the domestic cat (Felis catus), an obligate carnivore. Chemical Senses, 2023

This article is for general information and is not veterinary advice. Talk to your vet about your own cat — they know the animal in front of them.

Choolip products are food supplements, not medicine. They are not intended to diagnose or manage any medical condition. If your cat has been diagnosed with a condition, their diet should be set by your vet.