March 25, 2021

Can Dogs Eat Tuna? Vets explain possible health issues

girl gives dog tuna
Veterinarian Dr. Ivana Crnec, DVM
Published by Emma Hughes

Vet Approved

Fish is included in dog foods for a few reasons; for example, it is a high protein food and has valuable omega-3 fatty acids.

So, you might think that offering your dog tuna is a great idea; after all, the fish is inexpensive, sold at most all stores and supermarkets, and is versatile (you can make many meals out of tuna). Many readers ask, "Can my dog eat tuna," and we can't wait to answer that question.

However, although it may feel like there is no reason not to pop open a can of tuna for your dog, feeding it may not be such a good idea. Read on to discover why.

Can Dogs Eat Tuna?

No, dogs should not eat tuna, with light canned tuna being the exception that can be offered in moderation. Tuna, in general, contains too much mercury and may cause mercury poisoning if fed regularly to dogs. Canned tuna also is high in sodium, so follow feeding guidelines to ensure your dog's health.

As a general rule of thumb, tuna is not a dog-friendly food.
- Dr. Ivana Crnec, DVM

Although dogs are omnivores, and they can eat both plants and meat, not all foods are safe and healthy for them. High-quality dog food is the basis of a balanced diet that fills your dog's dietary needs, and only 10% of their daily food intake should come from treats and other foods.

And as you can see, tuna is not the best choice if you want to treat your pup to something delicious yet healthy. Mixing tuna with dog food is not a good idea in the long run. A little, tiny bite of tuna won't be toxic to your dog, but they should not eat a whole can or be given tuna daily.

Raw tuna for dogs is also not ideal. The reason is mercury. Actually, it is best to avoid most kinds of tuna. Cooked and grilled tuna, raw tuna, and canned tuna in both oil and water should be avoided as well.

You can, however, serve your dog light canned tuna fish – as long as it is in moderation.

The difference is that "white" tuna is albacore, which can be very high in omega-3 fatty acids but also in mercury. "Light" tuna, however, is made from skipjack, yellowfin, bigeye, or a combination of them. It's not so high in mercury and is OK for dogs in small amounts.

Puppies must avoid all kinds of tuna. It is advised that you do not give puppies tuna fish of any kind. Puppies should only be given a special diet as prescribed by their vet. After all, they are growing and developing and should only eat safe and wholesome foods.

Dogs love tuna and will certainly eat it if given a chance. As a result, owners have to be responsible and keep tuna away from their canine companions unless it's the light canned tuna and you're keeping the amounts small.

Let's look at a few health benefits this type of tuna can have on your dog before moving onto the health risks you definitely need to be aware of before considering feeding it.

Health Benefits: Is Tuna Good for Dogs?

The only safe canned tuna for dogs is canned light tuna. As you may have guessed, this type of tuna fish contains some health benefits. Here are some advantages to feeding this type of tuna to your pup as a treat:

High in protein

The protein in tuna helps with muscle growth and is a low-fat food. If you've got a very active dog, canned light tuna is a great protein-rich treat for him or her.

After all, dogs need a lot of protein to stay healthy and active– and to have energy that keeps their body healthy.

tuna fish

It Contains Helpful Omega-3 Fatty Acids

Did you know your dog's shiny coat comes about as part of omega-3 fatty acids? It's true. Your dog will enjoy better skin and coat health, improved eyesight, and healthier blood pressure when they get adequate omega-3 fatty acids.

It's also great for cardiovascular health because omega-3's reduce the omega-6 fatty acids plus the "bad" or LDL cholesterol, which can build up in arteries. Your dog is less likely to experience cardiovascular disease if he is getting enough omega-3s.

Since tuna contain a lot of omega-3 fatty acids (EPA and DHA), it can be an occasional good treat for your dog as long as you stick to light canned tuna.

Full of helpful nutrients

Tuna fish contains many helpful vitamins and minerals. For example, dogs can get a heaping helping of Vitamin D from just 3 oz of canned light tuna. Your dog will also enjoy iodine, phosphorus, magnesium, selenium, potassium, and iron as part of their serving.

Thanks to tuna fish being loaded with helpful vitamins, your dog can enjoy a healthier immune system. For instance, there is Vitamin B12, which is necessary for DNA production. Also, this helps dogs create red blood cells and avoid anemia. Vitamin D, on the other hand, helps guard the immune system against disease.

Great for Weight Loss

Got a heavy dog that needs to drop a pound or two? Thanks to the high protein but low-fat content of tuna, your dog will enjoy a full feeling and have less of a desire for other treats.

If you're looking for a tasty protein-filled yet healthy treat, light canned tuna or a small piece of tuna steak could be an excellent choice.

However, although tuna can have its benefits, there are many health risks that you should know before you go dishing out this delicious snack.

Health Risks: Is Tuna Bad for Dogs?

Although there are some benefits, tuna, in general, is not great for dogs; after all, only canned light tuna or a tuna steak is suitable for dogs.

In most cases, the risks of feeding tuna outweigh the benefits.
- Dr. Ivana Crnec, DVM

Below, you will find three main reasons why tuna should not be fed to your dog on a regular basis. It’s also good to remember that fish are a common allergen in dogs. If it’s your first time feeding tuna to your dog, monitor them for 24 hours for any symptoms of fish allergy, such as

  • itchy skin
  • vomiting
  • diarrhea
  • hyperactivity
  • weight loss
  • lack of energy

Also, immediately discontinue feeding tuna and contact a vet for more advice if you suspect your dog has fish allergy.

Possible Mercury Poisoning

Fresh tuna contains very high levels of mercury as compared to other kinds of fish, like salmon or tilapia. As a result, eating too much of the fish can lead to mercury poisoning. Mercury poisoning has fatal health consequences for dogs.

Mercury enters the rivers, streams, and lakes, plus our oceans, due to industrial work. One such industry that is behind all this is coal-powered electricity.

Mercury levels then build up in the fish, and the larger the fish and the longer it stays alive, the more the mercury builds up in its body tissue. The reason for this is because tuna feed on smaller fish that are already contaminated with mercury.

Thanks to tuna fish being exceptionally large creatures, they have very high mercury levels. And because dogs weigh less than people, they are more prone to mercury poisoning.

The symptoms of mercury poisoning include anxiety, nervousness, kidney damage, loss of hair, and blindness, plus bloody/watery diarrhea, vomiting blood, loss of sensation in the paws, loss of coordination, and tremors. A small amount of any tuna on occasion will not harm your dog, but if you have been feeding tuna to your pet regularly and you notice these symptoms, it's important to ask a vet for assistance.

Possibility of parasites and bacteria

Raw tuna should never be fed to your dog, thanks to parasites like anisakadie and opisthorchiidae and bacteria like salmonella. The dog could end up contracting a foodborne illness that triggers symptoms such as diarrhea, vomiting, and fever.

Again, if your dog has eaten raw tuna and is experiencing these symptoms, it's best to ask a vet to help you assess the situation.

Sodium Levels Are High

We tend to think of seafood as being heart-healthy. But canned tuna is high in sodium, and high sodium levels are associated with high blood pressure, which can lead to heart disease or stroke.

Therefore, canned tuna can not be considered something healthy to feed to your dog on a regular basis since their diet should be fairly low in sodium. Although rare, it is even possible for dogs to develop salt poisoning.

Cat Food Dangers

Do you own a cat? Many cat foods contain tuna fish, and dogs love to eat out of the cat bowl. Be mindful that your dog isn't doing this, so he or she doesn't end up sick.

Cats and dogs have very different nutritional needs, after all, so trying out your kitties food once or twice may not be dangerous, but in the long run, you should ensure that both animals are fed a diet that takes into consideration their specific dietary needs.

Feeding Guidelines: Tuna for Dogs

Below you will find some helpful guidelines to use when feeding your dog light canned tuna:

How Much Tuna Can I Give to My Dog?

This is dependent on the size of your dog. Once a week, one or two spoonfuls are appropriate for small dogs, and larger dogs may have a little bit more, such as three to four spoonfuls, once or twice a week.

How Often Can I Feed My Dog Tuna Fish?

Tuna fish is best kept as a once or twice-a-week treat. Because it's high in sodium and mercury, you don't want tuna as a staple food but rather as a small tasty treat that is offered a maximum of twice a week.

tuna steak

How to Prepare Tuna for Dogs?

When choosing canned tuna, be sure you only choose light canned tuna (and preferably tuna in water instead of tuna in oil). Albacore and other varieties tend to be too high in mercury. You can start by feeding your dog a little of this tuna at a time to see how they react. Stop feeding if they don't care for it or have a negative reaction like diarrhea (some dogs have sensitive stomachs).

Canned light tuna and properly prepared tuna steaks make a nice once-in-a-while treat.

If you would like to serve cooked tuna to your dog as a very rare treat, purchase tuna steaks. Bake or broil the fish as your method of preparation. Be sure you avoid all seasonings and salt and make sure any bones present in the meat are removed. Dogs will gobble up the fish faster than you know, so it's important to ensure the steak is deboned properly. Otherwise, the bones could pose a choking hazard or cause a blockage in the gastrointestinal tract.

What about tuna with mayo, tuna steak, or tuna salas?

Tuna with mayo will not hurt your pet in small amounts. However, dogs should not eat this in large quantities because it provides little nutritional value for your pet. Mayo is also high in fat, which is not good for dogs and may cause diarrhea and weight gain. One small spoonful won't hurt your dog, however

Tuna steak is OK for dogs provided the owner prepares it responsibly. Remember, only baking or broiling are the appropriate methods of cooking, and you should avoid all kinds of salt, spices, and seasonings.

Tuna salad is not very nutritious for dogs, but one small spoonful to show your dog how it tastes won't harm them. It has little nutritional value for dogs, so it should not be served as a staple food. Some canned tuna salad versions contain vegetables that can be toxic to dogs (such as onions) and are heavily spiced, so avoid those as well.

Nutrition Facts

Per 100g of light canned tuna, you get the following:

  • 116 calories
  • 82g total fat
  • 30mg cholesterol
  • 50mg sodium
  • 0g total carbohydrates
  • 25g protein

Light canned tuna also contains the following helpful vitamins and minerals:

  • Vitamin D
  • Selenium
  • Iron
  • Omega-3 fatty acids

As you can see, tuna can be considered a low-fat protein. In that sense, it may have health benefits – and, of course, your dog probably loves the taste.

Still, canned tuna is often very high in sodium, and tuna, in general, contains too much mercury to be fed to your pup regularly.

Summing Up – Can Dogs Have Tuna?

Dogs are generally advised to avoid tuna, except for light canned tuna fish. Owners may prepare tuna steaks for their pet, but only by broiling or baking the fish and avoiding seasonings of any kind.

Canned tuna is OK also, but only if serving light canned tuna to your pet. You must also be mindful of the amount served to your pet- it is important to take the weight of your dog into consideration. Moderation is always the key when serving your dog anything outside of their standard diet.

Indeed, canned light tuna and properly prepared tuna steaks make a nice once-in-a-while treat. But keep in mind this is not a staple food. Stick with food recommended by your vet, clean water, and plenty of exercise for your pet's good health.

Vet's Comment

As a general rule of thumb, tuna is not a dog-friendly food. If adequately prepared, certain types of tuna can be healthy to dogs, but in most cases, the risks of feeding tuna outweigh the benefits. From transient gastrointestinal upsets through foodborne diseases to life-threatening mercury poisoning – eating tuna comes with many cons.

Do not get me wrong, if your dog steals few tuna bites, there is nothing to be concerned about. My picky eater dog loves the smell of tuna, and given the opportunity, she will do whatever it takes to have a few mouthfuls.

So, basically, occasional stealing accidents and rare tuna treats are not harmful. However, it is highly unadvisable to feed tuna regularly or as part of the dog's standard menu.

- Dr. Ivana Crnec, DVM

Ivana Crnec doctor of veterinary medicine

Vet-Approved by
Dr. Ivana Crnec

DVM

Ivana Crnec is a Doctor of Veterinary Medicine specialized in domestic carnivores. She graduated from the University Sv. Kliment Ohridski, Faculty of Veterinary Medicine in Bitola, Republic of Macedonia. Ivana is a certified canine nutritionist and also certified in HAACP food safety system implementation. She currently works as a veterinarian while completing her postgraduate studies. Her research has been published in international journals.

NOTE: Advice provided within this article by FeedingMyPet.com is not a substitute for veterinary advice. Please discuss your dog's specific dietary needs (based on his breed, weight, age, and health status) with a veterinarian.

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