Small amounts of cooked or canned tuna are generally safe for dogs, but mercury content means tuna should be an occasional treat, not a regular part of the diet.
In moderation only — mercury is the main concern
Tuna is safe for dogs in small amounts and is a good source of protein and omega-3 fatty acids. However, tuna — especially larger species like albacore — accumulates mercury. Regular or large servings can lead to mercury toxicity over time. Occasional small amounts are fine.
Why does mercury matter for dogs?
Mercury is a heavy metal that accumulates in fish that are high on the food chain. Tuna is a large predatory fish that can contain significant mercury levels. Dogs that consume too much mercury over time can develop mercury poisoning: symptoms include loss of coordination, muscle weakness, loss of vision, tremors, and kidney damage.
Canned tuna vs. fresh tuna for dogs
| Type | Safe? | Notes |
|---|---|---|
| Canned light tuna (in water) | In moderation | Lowest mercury; plain water-packed, no added salt |
| Canned albacore (in water) | Less frequently | Higher mercury; limit more strictly |
| Canned in oil | Avoid | Too much fat; often has added salt |
| Canned in brine | No | Extremely high sodium |
| Fresh cooked tuna | In moderation | No added salt or seasoning; cooked thoroughly |
