Safety guide
Is Tuna safe for dogs?
A little plain cooked tuna now and then is fine, but its high mercury content means it should not be a regular food.
Tuna is not toxic to dogs, and a small amount of plain, cooked tuna occasionally is generally safe. The concern is mercury: tuna is a large, long-lived fish that accumulates significantly more mercury than smaller species, and regular feeding risks a gradual build-up that can harm the nervous system and kidneys over time. If you offer tuna, use plain tuna canned in water (never in brine or oil, which add excess salt and fat), give only a small amount, and keep it an occasional treat rather than a staple. Lower-mercury fish such as cooked salmon or whitefish are better regular choices.
Symptoms to watch for
- Digestive upset — vomiting or diarrhoea, especially from oily or brined tuna
- Excessive thirst (from salted or brined varieties)
- With chronic overfeeding: incoordination, tremors or hair loss (signs of mercury build-up)
What to do immediately
- 1Stop offering tuna and switch to a lower-mercury fish for regular treats
- 2Provide fresh water, particularly if the tuna was salted or in brine
- 3Monitor for stomach upset over the next day
When to call your vet
Your dog has been eating tuna frequently, or shows persistent vomiting, diarrhoea, tremors or unsteadiness.
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