Can Dogs Eat Tuna? Yes, but Only Occasionally

What it gives your dog

Tuna is an oily fish with lots of protein (25-30 g per 100 g, canned and drained) and omega-3s. The problem is that, as a large, long-lived predator, it accumulates methylmercury, a metal that in repeated doses damages the nervous system and kidneys. The bigger the species, the more mercury: bluefin has the most, while yellowfin and albacore fall in between (canned light tuna, mostly skipjack, is usually lower). That is why it should not be fed daily, and sardines or mackerel are lower-mercury alternatives.

Canned tuna also usually contains salt (around 1 g per 100 g) and, if packed in oil, a lot of fat. Skip versions in marinade, tomato or with spices.

How to serve it

Canned in water, drained; "low sodium" or "no salt added" if you can find it
In oil, only well drained and in a smaller amount
Fresh, cooked in a dry pan or steamed with no salt
As an occasional treat, not the base of their diet
Never marinated, in tomato, spicy or with sauces

How much can they eat?

Once or twice a week at most: small dog (under 10 kg / 22 lb), 10-20 g of drained tuna (one tablespoon); medium dog (10-25 kg / 22-55 lb), 20-40 g (1-2 tablespoons); large dog (over 25 kg / 55 lb), 40-60 g (about 2 oz). A small 80 g European-style can weighs about 50-55 g drained; a standard 5 oz US can yields roughly twice that.

Risks

Accumulated mercury if fed often
Salt in canned tuna
Fat from oil: diarrhea or pancreatitis in sensitive dogs
Canned tuna with sauces, spices or marinade
Raw: Anisakis if not frozen, and bacteria (we do not recommend it raw)

Frequently asked questions

Can dogs eat tuna in oil?

Occasionally, yes, if you drain it well. The oil is not toxic, but it adds a lot of calories: a can in oil has far more fat than one in water, and in sensitive dogs it can cause diarrhea or, in predisposed dogs, pancreatitis. If you have the choice, pick tuna in water; if you only have it in oil, drain it, rinse it and give half the amount.

Can puppies eat tuna?

It is better to offer other fish. Puppies are small and their nervous system is still developing, so their mercury intake should be kept to a minimum. A teaspoon of tuna in water as an exception is not a problem, but for regular fish, cooked sardines, hake or salmon are better options.

Can dogs eat raw tuna?

We do not recommend it: cooked in a dry pan with no salt is the simplest and safest option. On a raw diet, only after freezing for at least a week at −18 °C (0 °F) and from a trusted fish counter. Tuna has less Anisakis than other fish, but it is not free of it, and freezing does not kill bacteria. Either way, the amount should be small and occasional because of the mercury.