Cats and tuna are famously a match, and most cats would happily eat it all day, but that is exactly the problem. A little plain tuna now and then is a fine treat, but tuna should never be a cat’s main food. It is not a balanced diet, and a tuna-heavy one can actually cause health problems, quite apart from turning a cat into a fussy tuna addict. So the honest answer is yes to the occasional small treat, and a firm no to tuna as a regular meal.
Tuna as a treat, not a diet
The key to tuna is understanding that human tuna is a treat food for cats, not a complete one, and treating it as a meal is where things go wrong.
Plain tuna is very palatable to cats and provides protein, so a small amount as an occasional treat is fine for most cats. But tuna made for people is not formulated to meet a cat’s full nutritional needs the way a complete cat food is. It lacks the right balance of nutrients, including adequate taurine and vitamin E, so a cat fed largely on tuna can end up deficient. There is also a specific risk with oily fish: too much of it, without enough vitamin E, can cause a painful inflammatory condition of the body fat. On top of the nutrition, tuna is so tempting that some cats become hooked on it and start turning their noses up at their proper, balanced food, which creates its own problem. For all these reasons, tuna belongs firmly in the occasional-treat category.
How to give tuna safely
If you do want to treat your cat to a little tuna, a few simple choices make it a safe indulgence.
Choose plain tuna tinned in spring water rather than in brine or oil, since brine is very salty and oil adds unnecessary fat, and make sure it has no added salt, flavourings, or other ingredients. Give only a small amount, a little flaked over the top of a meal or as a standalone treat, not a whole tin, and keep it occasional rather than daily. Never give tuna that has been seasoned or mixed with things like onion or garlic, which are toxic to cats. And remember that cat foods containing fish are a different thing entirely: those are formulated to be nutritionally complete, so they are fine as a regular diet in a way plain tuna is not.
So, can cats eat tuna? Yes, a small amount of plain tuna as an occasional treat is fine for most cats, but it must not be a staple. Human tuna is not a balanced diet, a tuna-heavy one risks deficiency and other problems, and regular tuna can turn a cat into a fussy addict. Treat it as the occasional indulgence it should be, choose plain tuna in water, and let a complete cat food do the real feeding. For the wider picture of feeding cats safely, see our guide to safe and toxic foods for cats.
Common questions
- Is tuna safe for cats?
- A small amount of plain tuna, ideally tinned in water rather than brine or oil, is fine as an occasional treat for most cats. The problem is tuna as a regular food. It is not nutritionally complete, and a tuna-heavy diet can cause health problems, so it should stay an occasional treat, not a staple.
- Why can't cats eat tuna every day?
- Tuna made for humans is not a balanced diet for a cat. It lacks nutrients cats need, such as adequate taurine and vitamin E, and too much oily fish can cause a painful condition affecting the body fat. Cats can also become 'addicted' to tuna and start refusing their proper food, so it is best kept occasional.
- What kind of tuna is best for cats?
- Plain tuna tinned in spring water, with no added salt, brine, oil, or flavourings, given in a small amount, is the best choice for an occasional treat. Avoid tuna in brine or oil, and never give tuna that has been seasoned or mixed with things like onion. Cat food containing fish is formulated to be balanced, unlike plain tuna.
