Tuna can.

Is It Good To Mix Tuna Into Dog Food?

Written By Vedrana Nikolic | B.A Ethnology & Anthropology, M.A Semiotics.
Edited & Fact Checked By Renae Soppe | B.A Journalism & Science. 
Last Updated: 17th January 2024

Many pet owners love to spoil their furry companions with occasional treats or special meals. One popular choice is mixing tuna with dog food.

However, before you indulge your canine friend, it’s a good idea to go over the benefits, risks, and recommended amounts of tuna in your dog's diet. In short, tuna is a healthy option for dogs, with one big caveat: the mercury content. Is that something you should be concerned about or is tuna fine as an addition to your dog’s dinner bowl? Let’s discuss.

Is Tuna Safe for Dogs to Eat?

The general opinion on feeding tuna dogs is that yes, it is OK to feed tuna (tinned or fresh) occasionally. However, this advice always comes with the note “use in moderation”. Tuna can be a great treat, but it is not ideal as the primary source of protein for your dog. This is primarily due to the concerns related to high mercury concentrations in tuna. 

Not everyone agrees with this, though. The American Kennel Club (AKC), for example, advises against feeding tuna to dogs, specifically due to high mercury levels (1). On the other hand, we’ve seen dog food formulas that include tuna, and we’ve seen dogs being fed tuna as a food topper on a semi-regular basis without getting mercury poisoning. So what gives?

Well, mercury poisoning is a real risk that shouldn’t be ignored - in dogs as well as in humans. How cautious you want to be about that is your own choice. If you want to stay on the safe side, you might want to avoid tuna altogether like the AKC suggests. At the same time, there is no evidence (anecdotal or otherwise) that occasional consumption of tuna can harm your dog.

Personally, I wouldn’t choose it as the main protein source or even feed it on a regular basis. But as an occasional treat, I think tuna is completely fine.

Another thing to keep in mind if using tuna from the tin is the sodium levels, which are typically high in tinned fish. This is a general concern when feeding ingredients designed for human consumption - there might be additives included which are safe for us to eat, but might be harmful to dogs in high concentrations. Such is the case with salt. It’s not a huge concern if you feed moderate amounts and only occasionally, but it is something to keep in mind.

Is Mercury a Real Concern?

Well, mercury poisoning is a real thing and it can affect both humans and animals. Moreover, mercury can accumulate in the body over time which can lead to health complications if it goes unnoticed. However, mercury poisoning in dogs is a complication that occurs very rarely.

But, tuna in particular is the food item that’s likely to contain more mercury than anything else your dog will ever eat.

“Tuna is a notorious mercury-containing fish so this was of particular concern to us. Tuna not only contains high levels of mercury, but most of it is in the methyl-mercury form. Methyl-mercury is a potent neurotoxin. Small doses can cause adverse health effects in animals and humans.” - Dr Sarrah Dunham-Cheatham (2)

On top of that, there is simply not enough research to tell us how much mercury is too much when it comes to dogs:

“There is no question that excessive levels of this metal should not be present in foods. Unfortunately, a safe upper limit in pet foods has not been established by either the Association of American Feed Control Officials (AAFCO) or the National Research Council (NRC). Nor does there exist a compulsory requirement for pet food companies to test their products for mercury (or any other heavy metal)” - Linda P. Case, The Science Dog (3)

It all sounds pretty scary, but in the end, there is no reason to believe that occasionally eating tuna in reasonable amounts is going to harm your dog.

Is Tuna Good for My Dog?

If we put the mercury issue aside, tuna would be a really nice addition to a dog’s diet. For starters, it is packed with protein, which is just what canines need.

Additionally, fish is a great source of omega-3 fatty acids which are beneficial to dogs in a variety of ways. For example, dogs that eat a diet rich in these fatty acids typically have a healthy skin and a shinier coat.

Finally, fish skin can be a good source of collagen which can help maintain bone and skin health in senior dogs (4).

How Much Tuna Should I Add to My Dog’s Food?

Well, there is no hard and fast rule when it comes to how much tuna your dog can eat. We recommend regarding tuna as a treat. That means, make sure the tuna doesn’t make up more than 10% of your dog’s daily food consumption. If, on top of that, you stick to feeding tuna only occasionally (1 or 2 times per week, and preferably not every week), you should be on the safe side.

Final Thoughts

Once again, tuna is OK (and even healthy) as an occasional treat for your dog. If you have been feeding your dog tuna, there is no need to panic, they are most likely fine. But, tuna does usually contain more mercury than most other types of fish, so some caution is advised.

If your dog loves eating tuna, there might also be other viable options to consider. Tinned sardines or mackerel are just as easy to find as tuna and aren’t too expensive. These smaller fish are less of a risk than tuna when it comes to mercury poisoning, so they might just be the perfect alternative.


  1. Ripley, K. August 2, 2022. “Can Dogs Eat Tuna”. American Kennel Club. Retrieved September 19, 2023. https://www.akc.org/expert-advice/nutrition/can-dogs-eat-tuna/
  2. E. December 13, 2021. “Is There Mercury In Pet Food?”. Dogs Naturally. Retrieved September 19, 2023. https://www.dogsnaturallymagazine.com/is-there-mercury-in-pet-food/
  3. Case, L. P. January 15, 2020. “Mercury Rising?”. The Science Dog. Retrieved September 19, 2023. https://thesciencedog.com/2020/01/15/mercury-rising/
  4. Gillette, L. August 7, 2023. “Can Dogs Eat Fish?”. PetMD. Retrieved September 19, 2023. https://www.petmd.com/dog/nutrition/can-dogs-eat-fish

Vedrana Nikolic

Vedrana Nikolić is Gentle Dog Trainers Canine Coach, Professional Writer, Anthropologist & dog lover.

With a Masters Degree in Semiotics & Bachelors Degree in Anthropology, studying the communication between animals and humans, Vedrana is able to use her expertise to analyse and review dog products and write informative posts on canine behaviour and training.

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