Can Dogs Eat Tuna?
The short answer is yes â dogs can eat tuna in small, occasional amounts â but it's one of the fish you need to be most careful with. Tuna is perfectly safe as a rare treat, but it should never be a regular part of your dog's diet.
The reason? Mercury. Tuna is a large, long-lived predatory fish, and large predatory fish accumulate mercury through a process called bioaccumulation â they eat smaller fish, who ate even smaller fish, and the mercury concentrates up the food chain. Over time, regular tuna consumption can lead to mercury poisoning in dogs.
Why Mercury Is a Problem for Dogs
Mercury toxicity in dogs can cause serious neurological damage. Unlike humans, dogs are typically much smaller, and even moderate mercury exposure can cause harm. The key symptoms of mercury poisoning include:
- Loss of coordination and balance problems
- Tremors or muscle weakness
- Kidney damage (mercury is nephrotoxic)
- Vomiting and diarrhoea
- Blindness in severe cases
- Hair loss
â ïļ The Mercury Risk Is Real
According to the US FDA, albacore (white) tuna has mercury levels approximately 3Ã higher than skipjack (chunk light) tuna. For dogs, who weigh far less than humans, the safe threshold is reached much faster. A single large portion of tuna is unlikely to cause harm â but weekly feeding over months can accumulate to toxic levels.
Canned vs Fresh Tuna: Which Is Safer?
â Canned Tuna (In Water)
- Canned skipjack (chunk light) is the lowest mercury option
- Choose tuna packed in water, not oil
- Rinse before serving to remove excess sodium
- Occasional small amount is fine
â ïļ Albacore / Fresh Tuna
- Albacore has 3Ã more mercury than skipjack
- Fresh tuna steaks are high-mercury
- Tuna in oil â too much fat, can cause pancreatitis
- Tuna with salt, spring water with flavouring â avoid
Safe Serving Sizes for Tuna
If you do want to give your dog tuna as an occasional treat, keep the amounts small:
- Small dogs (under 10kg): 1 teaspoon of canned skipjack tuna, no more than once a week
- Medium dogs (10â25kg): 1 tablespoon, once a week at most
- Large dogs (25kg+): 2â3 tablespoons, once a week at most
ðĄ Our Recommendation
Rather than worrying about mercury limits, simply use better fish instead. Sardines, mackerel, and salmon are higher in omega-3, lower in mercury, and far safer to feed regularly. Save the tuna for a rare occasion.
Fish Safety Comparison: Mercury Levels
Not all fish are equal. Here's how common fish compare for dogs, from safest to most risky:
| Fish | Mercury Level | Omega-3 | Safe for Regular Feeding? |
|---|---|---|---|
| ð Sardines (canned in water) | Very Low | Very High | â Yes â best choice |
| ð Mackerel (Atlantic) | Low | Very High | â Yes â excellent |
| ð Salmon (cooked) | Low | High | â Yes â must be cooked |
| ð Herring | Low | High | â Yes |
| ð Tuna â Skipjack (canned) | Medium | Medium | â ïļ Occasional only |
| ð Tuna â Albacore | High | Medium | â Avoid or very rarely |
| ð Swordfish | Very High | Medium | â Avoid |
| ð King Mackerel / Shark | Very High | Medium | â Never |
Why Sardines Are the Superior Choice
If you want your dog to benefit from fish â and they absolutely should â sardines are hands down the best option. Here's why:
ð Lowest Mercury
Sardines are tiny, short-lived fish. They barely have time to accumulate mercury before they're harvested. Even daily sardine feeding is safe for most dogs.
ð High Omega-3
Sardines contain more EPA and DHA per gram than almost any other food. Omega-3 reduces inflammation, supports joint health, and makes coats glossy.
ðĶī Whole Food Calcium
The soft edible bones in canned sardines provide natural calcium â great for homemade dog food where calcium balance is important.
ð° Affordable
A tin of sardines in water costs less than a dollar and can last a small dog several servings. Better nutrition at lower cost than tuna.
Raw Fish â Is It Safe?
Raw salmon and trout can contain a parasite called Neorickettsia helminthoeca, which causes Salmon Poisoning Disease â a potentially fatal illness in dogs. This is a genuine risk, especially in the Pacific Northwest. Always cook salmon and trout thoroughly before giving it to your dog.
Sardines and mackerel in canned form are already cooked during the canning process, making them completely safe. If feeding fresh versions, cook lightly â steamed or poached is ideal.
ðĻ Signs of Mercury Poisoning â See a Vet Immediately
If your dog has been eating tuna regularly and shows any of these symptoms, contact your vet right away: loss of balance, tremors, difficulty walking, kidney-related symptoms (excessive thirst, reduced urination), or sudden behavioural changes.
The Bottom Line on Tuna
Tuna isn't toxic â a small amount as an occasional treat is fine. But given the mercury risk and the fact that far better fish options exist, there's really no strong reason to feed tuna regularly. Swap it for sardines or salmon and your dog will actually benefit more, not less.