Tuna is not a good treat for dogs. It is not toxic, and a bite stolen from a plate will not cause harm, but tuna is high in mercury, so it should never be a regular part of a dog's diet.

Can Dogs Eat Tuna?

Why

Tuna is not poisonous to dogs the way chocolate or onions are, and it does contain protein, omega-3 fatty acids, vitamin B12, selenium and niacin. The concern is mercury. PetMD notes that, according to the FDA, tuna has higher mercury levels than nearly all other commercial seafood, and the AKC advises against feeding it to dogs at all.

Tuna builds up mercury because it is a large, long-lived fish. The AKC explains that mercury released by industry ends up in waterways and accumulates in fish, and that dogs can be more sensitive to it than people because of their size and metabolism. Regular helpings are the problem, not a single accidental bite.

Risks to watch for

Feeding tuna often, or as part of meals
Albacore (white) tuna, which PetMD singles out as higher in mercury
Tuna packed in oil, which can upset the stomach and contribute to pancreatitis
Canned tuna with added salt
Raw tuna, sashimi and sushi, which can carry bacteria and parasites
Tuna salad and tuna sandwiches with mayonnaise, onion or seasoning
Any tuna for puppies or very small dogs

How to share safely

Do not plan tuna into your dog's diet. Salmon and whitefish are safer fish choices.
If your dog snatches a little plain tuna, there is no need to panic. Just do not make it a habit.
If you share any at all, use a small flake of plain tuna canned in water, drained, with no salt or oil added.
Do not give tuna to puppies, or to dogs on a prescription diet without asking your vet.

How much?

No regular amount of tuna is recommended for dogs. The AKC says a tiny amount, such as a bite stolen from a plate, will not cause mercury poisoning, and PetMD says tuna should be limited to very small, occasional amounts.

Treats, including human foods, should make up no more than about 10% of your dog’s daily calories.

Which fish is safer than tuna?

Salmon is a safer fish to share with a dog than tuna, according to PetMD, which singles out albacore tuna as higher in mercury. The AKC lists salmon, whitefish, herring, flounder and Arctic char as safer options. Any fish you share should be cooked, plain and boneless.

Signs of mercury poisoning in dogs

Mercury poisoning from tuna is unlikely after a single taste and is linked to repeated feeding. PetMD notes that severe cases can damage the kidneys and cause blindness, and that vets may treat it with IV fluids, medication, binding agents such as activated charcoal and, in some cases, dialysis. Call your vet right away if a dog that has eaten tuna regularly shows:

Vomiting, vomiting blood or watery diarrhea
Blood in the stool
Loss of appetite or lethargy
Tremors, loss of coordination or trouble walking
Anxiety or nervousness
Hair loss or vision loss
Loss of feeling in the paws
Straining or being unable to urinate, or a swollen belly

Canned tuna, raw tuna and tuna cat food

Canned tuna adds its own problems. The AKC notes that canned tuna often contains added salt or preservatives, and PetMD warns that tuna packed in oil can upset a dog's stomach and lead to pancreatitis.

Raw tuna is not safer than cooked tuna. The AKC says raw tuna carries the same mercury risk plus possible parasites and bacteria, and PetMD recommends cooking all seafood, so sushi and sashimi are off the table.

Tuna cat food is not a workaround. The AKC advises that dogs should not eat cat food, especially if it contains tuna, so feed cats where dogs cannot reach their bowls.

Common questions

Is tuna good for dogs?

Only in limited ways. Tuna is not poisonous to dogs the way chocolate or onions are, and it does contain protein, omega-3 fatty acids, vitamin B12, selenium and niacin. The concern is mercury.

Is tuna bad for dogs?

It can be. Risks to watch for: feeding tuna often, or as part of meals; albacore (white) tuna, which PetMD singles out as higher in mercury.

Are dogs allowed to have tuna?

Only in small amounts and the right form. Do not plan tuna into your dog's diet. Salmon and whitefish are safer fish choices.

← All foods

Sources

American Kennel Club (AKC). Can Dogs Eat Tuna?
PetMD. Can Dogs Eat Tuna?
ASPCA Animal Poison Control Center. People Foods to Avoid Feeding Your Pets.
Merck Veterinary Manual. Toxicology section.
American Kennel Club (AKC). “Can Dogs Eat…?” article series.

If your dog has eaten something toxic, contact your veterinarian or an emergency animal hospital right away. Do not wait for symptoms. In the US you can also call the ASPCA Animal Poison Control Center at (888) 426-4435 or the Pet Poison Helpline at (855) 764-7661 (fees may apply).