Can Dogs Eat Canned Tuna Fish? (Tinned Tuna Safe Or Not)

A tuna fish sandwich is probably one of the best lunches, especially in summer. A little dash of salt, pepper, maybe some lettuce or cucumber if you want that crunch. Delicious. But what about the leftover flakes in the can? Is your dog allowed to have a little nibble? 

Dogs can eat canned tuna fish. In fact, it can be considered a healthy treat for them to have every once in a while. However, tuna does come with some risks that you’ll want to consider – namely the potential mercury content and whether it’s in oil or brine. 

If you want to learn more about the benefits and dangers of tuna for your dog, this is the perfect guide for you. After all, we only want the best for you and your pup. 

Can Dogs Eat Canned Tuna in Sunflower Oil? 

This is the safer option between oil and brine, and if you drain the tuna thoroughly then it is safe to give your dog a little bit. This is because sunflower oil is lower in saturated fats than other oils and can even prove beneficial to your dog’s coat and skin in small quantities. 

However, you should keep in mind that too much oil can cause inflammation as well as weight gain. This is because the sunflower oil contains omega 6, which is good for their health but must be consumed alongside omega 3 to avoid inflammation and negative immune responses.

tuna chunks

Can Dogs Eat Canned Tuna in Brine? 

A very small amount of tuna in brine isn’t toxic, but it should certainly be avoided due to the high salt content. Too much salt can cause sodium poisoning in dogs, which is definitely possible considering the sheer levels of salt found in brine. 

Instead, you should look to buy tuna that is in spring water as it doesn’t contain salt or oils and is much safer for your dog to have. Even after you drain the brine from the tuna can, the salt remains in the fish and is still a risk to your dog. 

Can Dogs Eat Tuna Steak? 

This is a very important topic. There are videos out there of people feeding their dog bluefin tuna steaks raw because it is the best out there. Sure, it might be the best type of tuna for humans, but it really isn’t for dogs. 

In fact, raw tuna should be avoided completely as a treat for your dog. This is because it is more likely to cause stomach upsets for your dog than cooked fish as well as the fact raw tuna can contain parasites that are harmful to your pup. 

Furthermore, bluefin tuna contains the highest levels of mercury and should never be fed to your dog in raw or cooked form. If you really want to give them a tuna steak, you should pick a species that has lower mercury levels such as Albacore or Skipjack

These are the species that are used in canned tuna, which is why it is safer to give your dog a little spoon of tinned tuna rather than a steak. If you do give them a tuna steak, just remember to cook it thoroughly and stick to the safe varieties. 

tuna steak

Mercury in Tuna

Leading on from the following point, the mercury level in tuna is determined by both their size and lifespan. This is why bluefin tuna is not considered safe for your dog – it is the largest and the one with the longest life expectancy. 

But why is mercury such an issue? The cause is humans, as usual. Since a great deal of our waste and pollutants end up in the ocean, we increase the amount of heavy metals found in the water through erosion, rain, rivers, and us directly dumping waste in the sea. 

These heavy metals end up accumulating within the tissue of sea creatures, building up inside them every time they eat. This is because they end up ingesting mercury with each meal and it remains inside them permanently as their bodies cannot remove it. 

Tuna has a long lifespan for a fish, across all species, and this is why they have much higher concentrations of mercury than the other fish that we eat. Since it eats smaller fish, it ingests the mercury found in them and builds up high levels over the course of its life. 

However, there are some species of tuna that have less mercury inside them. As an example, the Skipjack is a very small species of tuna in comparison. Therefore, it contains three times less mercury than an Albacore tuna. 

This means that whenever you or your dog eat tuna, you are both ingesting a little bit of mercury. This isn’t concerning as the amounts are minimal and harmless, but if your dog eats too much tuna in a short period of time this can lead to mercury poisoning

The most common signs of mercury poisoning are tremors and excessive drooling alongside an upset stomach. If you notice these after your dog has eaten tuna, make sure you call the vet immediately so that they can get treatment. 

Many owners opt to feed their dogs white fish or salmon as they are beneficial to their diet (like tuna is) but also contain significantly lower levels of mercury that are not harmful to you or your dog. You will also find salmon and whitefish are popular ingredients in commercial dog foods. 

How Much Tuna Can My Dog Eat? 

Tuna should be given as a very rare treat. A little spoon on their food twice a month is the perfect amount for them, and they should never be allowed to eat a whole can in one sitting. Nor should they be allowed to have it more than a couple of times a month

To break it down further, you could give a large dog a can of tuna over the course of a week – spread out evenly across their meals. However, you could not give them any tuna the next week as there is a risk of mercury poisoning

For small dogs, you could give them half a can of tuna over the course of a week and then avoid giving them any the next week. However, it is best to just stick with a small spoon of tuna on their food every couple of weeks to stay safe and keep them healthy. 

Read Here: Can You Mix Tuna With Dog Food

Can Tuna be Harmful to Dogs?

Yes, tuna can be harmful to dogs. The amount of mercury found in tuna is concerning and certainly has the potential to lead to mercury poisoning in your pup. This is why it is so important to stick to very small amounts as a rare treat. 

This is the only real risk that tuna has for dogs, aside from whether or not the canned tuna is in oil or brine. As mentioned previously, uncooked tuna steaks can also contain parasites that might be harmful to your dog which is why it is best to cook them first. 

Of course, tuna does have some benefits as well. It is rich in omega 3, which is great for your dog’s skin, coat, and overall health. It is also an excellent source of protein, providing them with the energy they need for the day as well as keeping their muscles in good health

The thing is, there is plenty of other fish that offer these benefits (and more) without the risk of mercury poisoning due to their much lower levels. You also need to watch out for any canned tuna that has been left in herb and spice mixes as these can contain onion and garlic. 

Sometimes, it is better to be safe and stay on the side of caution rather than risk it – even if those puppy dog eyes are particularly sweet and sad. 


Can dogs be allergic to tuna?

Absolutely, your dog can be allergic to tuna. Fish allergies are actually fairly common in dogs. You can usually tell if your dog is reacting to the fish in their diet through the following symptoms:

  • Itchy skin
  • Ear infections
  • Obsessive chewing/licking of feet
  • Hair loss
  • Hotspots
  • Runny nose
  • Runny eyes

If you notice any of these symptoms in your dog, make sure you book them in at the vet to have an allergy test so that you can determine what’s causing it. 

Can puppies eat tuna?

Definitely, your puppy is safe to eat tuna. However, it is best to wait until they are over 12 weeks old so that their stomachs have a chance to become stronger. You should also make sure they only have a little bite (maybe two) once every few weeks. Keep it few and far between. 

Final Thoughts

Tuna is great, but it does come with risks. Mercury is a real and worrying issue, especially if your dog manages to get into a lot of tuna. However, a little bit of tinned tuna every now and again isn’t going to hurt and can have some great nutritional benefits.