Can cats eat tuna?
Written by Meowledge · Last updated
Only occasionally; it can’t replace balanced cat food.
Only as an occasional treat, not as a meal. Plain tuna now and then is not generally harmful. The problems on record come from large amounts of canned tuna or a diet built mostly on fish.
- How much
- Plain canned tuna given only occasionally — not as a replacement for a balanced cat food.
- When it becomes a problem
- The documented problems follow large quantities of canned tuna or a diet made up mostly of fish.
Treats count toward daily calories — the cat calorie calculator estimates the daily total.
Fine
- Now and then, as a treat
Avoid
- Large amounts of canned tuna
- Tuna in place of a balanced cat food
- A diet mostly of raw fish
- Tuna with onion or garlic
From Cornell Feline Health Center, the Merck Veterinary Manual and a peer-reviewed review of thiamine deficiency (sources below).
How to give tuna safely
Offer tuna only as an occasional treat, never a meal replacement; avoid seasoned tuna, and never feed raw fish regularly. See a vet if a cat on a fish-heavy diet develops appetite loss, listlessness, a belly that is painful to touch, wobbliness or seizures.
Signs that tuna is causing a problem
- Loss of appetite, listlessness, or a belly that is painful to touch (vitamin E deficiency / pansteatitis from a canned-tuna-heavy diet)
- Neurological problems, seizures, or muscle weakness that bends the head downward (thiamine deficiency from a sustained raw-fish diet)
How much tuna can I give my cat?
Keep it an occasional extra, not a daily portion. As a one-off treat, tuna is generally not bad for a cat — it is just not good for a cat as a habit.
Treats like tuna do not give a cat complete, balanced nutrition, so a balanced commercial cat food should stay the main diet. To see what your cat needs in a day, try the cat calorie calculator. The steps run in order: a one-off piece, a canned-tuna habit, then fish most of the diet — nothing is recorded against the first, vitamin E deficiency belongs to the second, and the thiamine and mercury questions to the third.
Can cats eat canned tuna every day?
No. Cats given large amounts of canned (tinned) tuna have developed vitamin E deficiency, which causes yellow fat disease (pansteatitis). Kittens and adults may go off food, act dull, or flinch when a hand meets the belly.
Cornell also reports that some cats that ate canned fish products meant for people developed potentially serious nerve problems (neurological disorders). It does not tie this to any amount. If fish has been most of the diet, ask a veterinarian about appetite loss, a dull cat, a belly that hurts when touched, a wobble, or a seizure.
Can kittens eat tuna?
There is no age threshold in the sources. Merck records vitamin E deficiency in kittens and adult cats alike after large quantities of canned tuna, so a growing cat is not the safer case.
Nothing in the sources gives a kitten a higher allowance than an adult cat; Cornell's recommendation is a nutritionally balanced commercial food, so tuna stays an occasional extra rather than a food to raise a kitten on.
What can I feed my cat if I run out of cat food?
Get a balanced commercial cat food as soon as you can; that is what vets generally recommend. Tuna is a treat, not a meal replacement. For anything else in the cupboard, check the food list.
A commercial cat food may contain fish. Merck says the heat used to can it is enough to destroy thiaminase, so that can is not the same thing as tuna packed for people.
Can cats eat flavored or seasoned tuna?
Not if it contains onion or garlic. Raw, cooked or concentrated onion and garlic, including onion powder, can destroy a cat's red blood cells and cause anemia. Check the label and stick to plain tuna. See why onions are toxic.
The same manual ties this toxicosis most often to concentrated forms: dehydrated flakes, powders, or dry onion soup mixes.
Is raw tuna safe for cats?
Not as a regular food. Some raw fish contains thiaminase, which destroys thiamine, and animals fed mostly raw fish have developed thiamine deficiency. Cooking destroys thiaminase, and so does the heat of canning.
Merck names raw freshwater fish and clams as sources of thiaminase. It does not say whether raw tuna contains it. Where cats do run short of thiamine, the same manual lists failure to grow, seizures, and a weak neck, with the head hanging down. Dogs and cats can also show an unsteady gait. Thiamine can likewise be destroyed by sulfur dioxide, or by overheating while a food is dried or canned, though those deficiencies are rare.
Is tuna bad for cats because of mercury?
It can be a long-term risk. Fish-based pet foods have been linked to chronic mercury poisoning in cats. Mercury builds up most in top predators, such as sharks.
Merck says mercury can build up a million-fold, from single-cell life in the silt to predators such as king mackerel and tilefish. Long-term limits on fish-based diets are described there too.
Sources
1.Merck Veterinary Manual — Nutritional Requirements of Small Animals
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thiaminases found in raw fish, which destroy thiamine... 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)... Kittens and adult cats may also develop anorexia, listlessness, hyperesthesia on palpation of the ventral abdomen... Thiaminases are found in raw freshwater fish and clams... Destruction of thiamine has also resulted from treatment of food with sulfur dioxide or overheating during drying or canning, but deficiencies are rare... those in cats include anorexia, failure to grow, neurologic dysfunction, seizures, and muscle weakness. Muscle weakness most commonly appears as ventroflexion of the head
2.Merck Veterinary Manual — Nutritional Requirements of Small Animals (thiaminase)
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Thiaminases are destroyed by cooking fish; therefore, although canned commercial cat foods may contain fish, the heat associated with canning is sufficient to destroy thiaminase
3.Cornell Feline Health Center — Feeding Your Cat
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It is generally recommended that cat owners purchase nutritionally balanced commercial foods... While giving your cat an occasional treat is not generally harmful, they are usually not a nutritionally complete and balanced source of nutrition and should only be fed occasionally... Some cats that have consumed canned fish products meant for humans have developed potentially serious neurological disorders
4.PMC — The Role of Thiamine and Effects of Deficiency in Dogs and Cats
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Thiamine deficiency has been documented in animals that have been fed diets containing predominantly raw fish... In dogs and cats, these can include ataxia... as well as seizures
5.Merck Veterinary Manual — Mercury Toxicosis in Animals
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mercury can bioaccumulate a million-fold from the lowest single-cell organisms that are exposed to elemental mercury in the silt of bodies of water to the highest predators (eg, sharks, king mackerel, and tilefish)... Commercial fish-based dietary products have been associated with chronic toxicosis in cats, and long-term chronic dietary exposure limits have been well described.
6.Merck Veterinary Manual — Garlic and Onion (Allium spp) Toxicosis in Animals
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toxicosis in these species is most commonly associated with ingesting concentrated forms of Allium, such as dehydrated flakes, powders, or dry onion soup mixes... Ingestion of raw, cooked, or concentrated forms of onions and garlic can result in Heinz body hemolytic anemia in cats
How sources are picked: methodology. Spot an error? Email hello@meowledge.app.