Can dogs eat tuna? Safe amounts, best types and risks

Yes, dogs can eat tuna, but it works best as an occasional treat rather than a regular part of the menu. Stick to plain canned tuna packed in water, ideally with no salt added, or fresh tuna that’s been cooked, because tuna accumulates mercury and many cans come with salt or oil.

This guide covers what tuna offers your dog, how much to give by size, which can to grab at the store, when to skip it and which fish make a better everyday choice.

Is tuna good for dogs?

Tuna has some real upsides:

• High-quality protein. Drained, water-packed tuna has roughly 25 g of protein per 100 g (3.5 oz), with all the essential amino acids.
• Irresistible flavor. Very few dogs turn it down, which makes it a high-value training reward.
• Vitamins and minerals. It’s rich in vitamin B12, niacin, vitamin D and selenium.
• Omega-3s (EPA and DHA). They’re there, although canned tuna has far less than salmon, mackerel or sardines.

And some downsides that call for limits:

• Mercury. Tuna are large, long-lived predators, so methylmercury builds up in their flesh. Bigger species carry more: solid white albacore typically has about three times the mercury of chunk light tuna, and bigeye is higher still. There’s no established safe intake for dogs; an occasional serving is low risk, but daily tuna isn’t a good idea.
• Sodium. Most canned tuna, even water-packed, has added salt.
• Fat from oil. Drained oil-packed tuna has close to twice the calories of water-packed, and the extra fat can cause diarrhea or, in susceptible dogs, pancreatitis.

How much tuna can a dog eat?

Treat tuna as a topper or reward: once or twice a week, and together with other treats it should stay under 10% of daily calories. A tablespoon of flaked tuna weighs about half an ounce (15 g).

For reference, a standard 5-ounce can yields roughly 3.5 to 4 ounces (100–115 g) of drained tuna, which is about four servings for a medium dog. If you add tuna on top of kibble, reduce the kibble slightly to compensate.

How to feed tuna to your dog safely

1. Pick the right can: chunk light, packed in water, with no salt added or low sodium.
2. Drain it thoroughly and give it a quick rinse if it contains salt.
3. Cook fresh tuna plain: seared in a dry pan, poached or steamed, with no salt, garlic, butter or spices. Remove the skin and any bones.
4. Flake it and mix it into meals, or use small pieces as rewards.
5. Keep it occasional. Rotate with other proteins such as plain cooked chicken without skin or bones or cooked eggs.

Risks and signs tuna didn’t agree with your dog

• Stomach upset. Vomiting or diarrhea, especially after oil-packed tuna or a large amount.
• Pancreatitis. A very fatty meal can trigger it in prone dogs, such as Miniature Schnauzers and overweight dogs. Look for repeated vomiting, belly pain, lethargy and loss of appetite.
• Fish allergy. Uncommon but possible: itching, recurring ear infections or loose stools.
• Too much mercury. Only likely with frequent, long-term feeding. Signs are neurological, such as tremors, wobbly walking or vision problems.
• Cuts from the can. A dog licking an open can can slice its tongue or muzzle on the sharp rim.

Better fish options for your dog

If you’d like to feed fish more regularly, these choices offer less mercury and more omega-3s:

• Sardines canned in water with no salt added. They’re small, short-lived fish with little mercury, and the bones in canned sardines are soft and edible.
• Salmon, always cooked and boned. Raw salmon and trout from the Pacific Northwest can carry the parasite behind salmon poisoning disease, which can be fatal to dogs.
• White fish such as cod, pollock or haddock, cooked plain and carefully deboned.

If you’re thinking about making fish a regular part of homemade dog food, have the recipe balanced by a board-certified veterinary nutritionist so it’s complete. And for the foods from your kitchen that dogs should never touch, see our list of toxic foods for dogs.

Frequently asked questions

Can dogs eat tuna packed in olive oil?

It isn’t toxic, but it’s not the best pick. Olive oil may be a healthy fat for people, yet for a dog it adds a lot of calories and can cause loose stools, and dogs prone to pancreatitis should avoid it. If oil-packed is all you have, drain it well, blot it with a paper towel and serve half the usual amount.

Can puppies eat tuna?

It’s better to wait. Puppies need a carefully balanced diet for growth, and their small size makes contaminants more of a concern, so tuna adds nothing their puppy food doesn’t already cover. If you want to use it as a reward, keep the pieces tiny and the treats rare, and lean on puppy training treats or plain cooked chicken instead.

Can dogs eat tuna every day?

It’s not recommended. Mercury builds up in the body over time, and a daily can also adds salt and calories that throw off a balanced diet. Once or twice a week, in the amounts in the table above, is a sensible limit. If you want a fish you can offer more often, sardines or cooked salmon are better candidates.

What if my dog ate a whole can of tuna?

For a medium or large dog, a can of water-packed tuna usually causes nothing worse than extra thirst or soft stools; oil-packed tuna makes vomiting and diarrhea more likely. Watch for repeated vomiting or belly pain over the next 24–48 hours, and check your dog’s mouth for cuts from the can. If you have a small dog, call your vet for guidance.

Can my dog eat cat food with tuna?

A one-time raid isn’t dangerous, but it shouldn’t become a habit. Cat food is higher in protein and fat than dog food and is formulated for a different species, so eating it regularly can lead to diarrhea, weight gain or, in sensitive dogs, pancreatitis. If your dog keeps stealing from the cat, feed the cat on a counter or shelf your dog can’t reach.

Sources

• U.S. Food and Drug Administration (FDA) and EPA: advice about eating fish and mercury levels by species.
• American Kennel Club (AKC): guidance on tuna and other fish in a dog’s diet.
• Merck Veterinary Manual: pancreatitis in dogs and heavy metal toxicity.
• Washington State University College of Veterinary Medicine: information on salmon poisoning disease in dogs.