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Can Dogs Eat Tuna? Occasionally and in Small Amounts

by Ben, co-founder · updated July 2026 · 1 min read

A dog and tuna
It depends

Small occasional amounts of cooked or tinned tuna (in spring water, not brine or oil) are fine for most dogs. Tuna sits high on the food chain, though, so it carries more mercury than smaller fish, which makes it a sometimes-food rather than a staple.

Why the caveats matter

Tuna itself is lean protein rich in omega-3s. The caveat is mercury: big, long-lived predatory fish accumulate more of it, and while the occasional sandwich-tin share is trivial, feeding tuna regularly builds exposure that smaller fish like sardines simply do not.

Preparation matters as much as the fish. Brine adds salt, oil adds needless calories, and raw tuna carries parasite and bacterial risks plus thiaminase, an enzyme that degrades vitamin B1. Cooked or tinned-in-water keeps it clean.

How to serve it safely

  • A spoonful or two for a medium dog, no more than once or twice a week at most.
  • Choose tinned tuna in spring water; skip brine, oil, and flavoured varieties.
  • No raw tuna, and no sushi sharing.
  • For regular fishy benefits, smaller oily fish (sardines, sprats) or a measured fish-oil supplement deliver the omega-3s with far less mercury.

When to ring the vet

ring your vet if

Excessive thirst after salty brine-packed fish · Loose stools when fish is new to the diet · Itching or ear flare-ups in dogs with suspected fish allergy, since fish is a recognised canine allergen

Frequently Asked Questions

Can dogs eat tuna in sunflower oil if I drain it?

Draining helps but plenty of oil clings on. Spring-water tuna is the cleaner choice; if oil-packed is all you have, keep the portion smaller.

Is fresh seared tuna steak okay to share?

Cooked through and plain, a small piece is fine. Rare or raw centres carry the raw-fish caveats, and seasoning usually includes salt, garlic or soy.

Can puppies have tuna?

Skip it. Puppies are more sensitive to mercury and their diet should stay complete and consistent while they grow.

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This article is for information, not diagnosis. If your dog has eaten something worrying, ring your vet or, out of hours, an emergency vet. Every dog is different, and your vet knows yours.

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