Is tuna good for dogs?
Fish in general is a genuinely good food for dogs — the American Kennel Club calls it “a healthy source of protein” that is “rich in omega-3 fatty acids, which may have health benefits, such as decreasing inflammation,” and notes “many dog foods contain fish.” Those benefits, though, belong to fish broadly, not to tuna specifically. A small serving of plain, cooked or water-packed tuna does deliver lean protein, and VCA Animal Hospitals notes a little tuna juice can even be used to tempt a sick or inappetent dog to eat.
Per USDA FoodData Central, light tuna canned in water (no salt added, drained) provides about 116 kcal, 25 g protein, and under 1 g of fat per 100 g — lean and protein-rich. The catch is mercury, and the type of tuna matters: the FDA states that “albacore tuna, also known as white tuna, typically contains three times more mercury than canned light tuna,” because albacore is larger and longer-lived. In the FDA’s ratings, canned light tuna is a “Best Choice,” while albacore/white is only a “Good Choice.” If you offer tuna at all, light/skipjack is the lower-mercury pick.
How much tuna is safe — and how often
Keep tuna small and occasional. The American Kennel Club deliberately stops short of endorsing a routine tuna portion, precisely because mercury accumulates with repeated feeding — frequency, not a one-time taste, is what creates the risk. Whatever you give should count inside the 10% treat rule (treats no more than 10% of daily calories). A spoonful shared rarely is very different from tuna as a standing item in the bowl.
Choose the right form: plain, water-packed, no-salt-added tuna, drained well — not tuna canned in oil or brine, which adds unnecessary fat and salt (AKC). Prefer light/skipjack over albacore/white for its lower mercury (FDA). Never season it, and don’t serve raw tuna, which the AKC notes “has the risk of carrying parasites or bacteria.” If your dog needs fish regularly, the AKC’s lower-mercury suggestions — salmon, whitefish, herring, flounder, Arctic char — are better routine choices.
Mercury and sodium: the reasons for caution
Mercury toxicity is rare in dogs and usually a result of long-term exposure, not one meal — but it is the reason tuna isn’t a staple. The AKC notes that mercury “builds up over time in the fish’s system,” and that for serious or repeated exposure, warning signs can include loss of coordination, tremors, vision loss, kidney damage, hair loss, vomiting blood, and bloody diarrhea — any of which warrant veterinary care. The Merck Veterinary Manual notes that with organic mercury, animals “do not show signs until several weeks after being poisoned,” and that neurologic damage “may be irreversible” — and that tuna products have specifically caused long-term poisoning in people and cats (cats being the more mercury-sensitive species). Separately, salted canned tuna adds sodium dogs don’t need; the Pet Poison Helpline warns large salt loads can cause vomiting, diarrhea, an unsteady gait, tremors, and seizures.
How to share tuna safely (and what to use instead)
If you want to give tuna, keep it to a small, occasional treat: choose plain, water-packed, no-salt-added light tuna, drain it well, add no seasoning, and offer just a little — mixed into food or given on its own — within the 10% calorie budget. Don’t make it a daily habit, and skip it entirely for puppies or dogs with kidney or neurological concerns unless your veterinarian approves.
For dogs that love fish, lean on lower-mercury options as the everyday choice. The AKC specifically recommends salmon, whitefish, herring, flounder, and Arctic char — all fully cooked, boneless, and unseasoned. These deliver the protein and omega-3 benefits of fish without tuna’s mercury-accumulation concern. If your dog eats some tuna and seems fine, the AKC’s advice is not to panic but to monitor for any signs of illness and contact your veterinarian with concerns.
Frequently asked questions
Can dogs eat canned tuna?
A small amount of plain, water-packed, no-salt-added canned tuna is not toxic to dogs, and the AKC confirms “a tiny amount will not cause mercury poisoning.” That said, the AKC does not recommend tuna as a regular food, because canned tuna “often contains added salt or preservatives that aren’t meant for dogs” and tuna is higher in mercury than many other fish. If you do offer it, drain it, skip oil, brine, and seasoning, choose light tuna over albacore, and keep it occasional. For routine fish, the AKC suggests lower-mercury options like salmon.
How much tuna is safe, and how often?
Keep it small and infrequent. Tuna should count within the 10% treat rule (no more than 10% of daily calories), and the AKC deliberately avoids endorsing a regular tuna portion because mercury “builds up over time” — it’s the frequency, not a single bite, that matters. If you’re choosing a type, the FDA notes albacore (“white”) tuna “typically contains three times more mercury than canned light tuna,” so light/skipjack is the safer pick. When in doubt, substitute a lower-mercury fish.
Is tuna’s mercury dangerous for dogs?
A one-off tiny portion isn’t — the AKC explicitly says a tiny amount won’t cause poisoning — but mercury is exactly why tuna isn’t a routine food. The AKC notes tuna’s mercury “builds up over time... and can lead to heavy metal toxicity,” and that dogs are “more sensitive to mercury” than humans. The Merck Veterinary Manual adds that mercury’s neurologic signs can take weeks to appear and may be irreversible, and that tuna has caused chronic poisoning in people and cats. For dogs, the simple safeguard is to keep tuna small and infrequent.
For related context, see our Can Dogs Eat Salmon? and Can Dogs Eat Shrimp?. To check whether your dog’s food contains any of these ingredients, paste the ingredient list into the KibbleIQ analyzer. For methodology context, see our published methodology.