Can Dogs Eat Tuna? [Ultimate Guide]

Does your dog start to beg when you open up a can of tuna? Or is it difficult to keep Fido away from the trash once you throw out the can or package that once contained the fish in your meal?

As with other foods, you might be tempted to share some with your dog. After all, it’s just meat, and all meats are good for dogs, right?

can dogs eat tuna
Can dogs eat tuna? The experts disagree with each other.

Well, the answer isn’t that simple. Even experts disagree on whether dogs can eat tuna. Some say that it’s okay as an occasional treat in small amounts. Others indicate you should try to avoid feeding tuna to your dog. However, if your pet grabs a small bite off your plate or from the trash while you’re not looking, it won’t cause too much harm.

Let’s take a look at why pet experts disagree on the subject and see if we can reach a conclusion based on the evidence.

Why Tuna Can Be Problematic

Feeding your dog tuna can be a problem because of high mercury levels. According to the FDA, tuna contains more mercury than other types of fish like salmon. Mercury can be harmful and toxic to dogs, especially when consumed in large amounts. Smaller dogs are more susceptible to mercury poisoning from tuna because of their weight. 

The less a dog weighs, the more impact foods and substances have on their systems. So a miniature schnauzer that gobbles down a full plate of tuna will stand a higher chance of developing side effects than a golden retriever that consumes the same amount of fish. 

The FDA states that humans should limit the amount of fish they eat if it contains high amounts of mercury. Species with lower amounts of the chemical are advised for humans. However, the FDA does not have a set of recommended consumption levels for dogs, and dogs tend to weigh a lot less than their masters.

In other words, if consuming a lot of tuna isn’t good for humans, the negative effects are going to be even worse for our pets. If you don’t want to expose your dog to foods with high levels of mercury, it’s best to avoid feeding them tuna.

How Can I Tell If My Dog has Mercury Poisoning?

can dogs eat tuna
So can dogs eat tuna? SHOULD dogs eat tuna? Is mercury poisoning really a concern?

So your dog just ate a can full of tuna, and now you’re worried. You’re not sure if you should take your pet to the veterinarian to induce vomiting or if there are going to be serious consequences. Typically, when a dog only consumes tuna once, it’s not going to lead to life-threatening side effects.

However, you should look for these telltale signs of mercury poisoning:

  • Seizures or convulsions
  • Vomiting, especially throwing up blood
  • Loose, watery, or bloody stools
  • Signs of kidney problems, such as drinking excessive amounts of water and not being able to urinate.
  • Sudden clumsiness or lack of coordination
  • Coma
  • Stomach discomfort, pain, and swelling
  • Exhibiting signs of anxiety and nervousness
  • Sudden blindness
  • A fascination with chewing or any behaviors that seem atypical for your pet.

These symptoms can develop quickly or take weeks and months to emerge. Sudden signs of mercury poisoning are more common in acute cases of exposure. Gradual symptoms are common in chronic cases or where the pet is exposed to smaller amounts of the toxin over time. 

What Should I Do if I Suspect Mercury Poisoning?

puppy at the vet with owners one adult one child
A cute puppy enjoying a Vet visit

If you suspect your dog has mercury poisoning and your pet is exhibiting symptoms, you should go to the vet right away. Take your dog to an emergency animal clinic if your regular vet is not available. In cases of poisoning, your pet must receive treatment as soon as possible to avoid further damage or even death. 

A vet will attempt to detoxify the animal and remove mercury from its system. They’ll also ensure your pet stays hydrated and gets treatments that reduce systemic inflammation. However, your dog may sustain irreversible damage to its kidneys, heart, and brain. Depending on the results of treatment, your pet may be able to sustain a good quality of life. You and your vet can make a joint decision based on the outcome.

What About Tuna in Dog and Cat Food?

When you look at the list of ingredients in dog or cat food, you might notice there’s some tuna in the formulas. Although commercial manufacturers of pet food sometimes use fish for protein, the tuna that’s in these foods usually do not contain a lot of mercury.

This is very different from feeding your dog a packet or can of raw tuna meant for human consumption. In most cases, you should separate cat and dog food if you own both types of animals. Cat food is not recommended for dogs and vice versa. Just as the nutritional needs of dogs can vary by age, weight, and medical condition, the types of nutrients canines and felines need for optimal health are different. 

Salmon is far more common in commercial dog food than tuna. If you’re concerned about exposing your pet to any fish, you can stick with dry or canned dog food that is made of beef or poultry for protein. Unlike canned tuna, canned chicken or turkey is safe for dogs to eat. It’s even recommended when pets have temporary digestive issues or upset stomachs. 

My Dog Has Kidney Disease. Should I Feed Them Tuna?

chocolate yorkie
A Chocolate Yorkie (aka a brown coat Yorkie) – expect this Yorkie color to lighten as the puppy ages.

Feeding a dog with kidney disease can present owners with several challenges. First, these pets need food with less protein so their kidneys don’t have to work as hard. There are prescription commercial foods for dogs with kidney disease that contain less protein. However, they tend to be bland, and some dogs have difficulties adjusting to the taste.

You might notice your dog doesn’t want to eat the food unless you enhance it with certain flavors. It can be difficult to discern whether your pet is eating less because of the food’s bland taste or their condition.

Kidney disease tends to decrease a dog’s appetite due to a higher amount of stomach acid and nausea. Pets with the disease can also become anemic because their bodies can’t produce or retain enough iron. 

a dog chows down on some good
A dog chowing down on some food. Some owners mix proteins like salmon into their dog’s kibble.

So some owners may be tempted to put a bit of tuna, salmon, or other meats into the prescription food. While this may make the meal more appetizing to your pet, it can wreak havoc on their kidneys. The excess protein can be difficult for their system to process and further complicate their condition. It’s better to use small amounts of low-sodium vegetable broth or small amounts of pumpkin.

Because toxins are also excreted through the kidneys and urine, you shouldn’t feed tuna to a dog with kidney disease. Ask your vet about commercial or raw diets that can help support your dog’s condition. Also, remember chronic kidney disease is progressive, and you may need your vet’s help adjusting your dog’s diet for the remainder of its life. 

Why Do Some Experts Give Tuna the Green Light?

labradoodle in party hat
My Labradoodle Max wearing his party hat. Stylish!

Some pet nutrition experts point to tuna as a source of lean protein that has high levels of anti-inflammatories known as omega-3s. Tuna fish also contains a large amount of potassium, selenium, and B vitamins. The thought is that the benefits of consuming tuna outweigh the risks, as long as the pet enjoys tuna as an occasional treat.

What this means is that these experts are not recommending you feed your dog a tuna-based diet or let them eat tuna several times a week. A small amount from your plate or a dog treat made with tuna a few times a month is okay. These pet nutritionists also recommend the tuna not contain any oil, spices, or added ingredients like onions. 

Some of these ingredients are toxic to dogs, such as onions and garlic. Canned tuna that’s in water can also reduce the number of unhealthy fats your dog consumes. Some of the canine treat recipes involving tuna include tuna pot pies and canned tuna baked with eggs. 

If you’re worried about your dog grabbing a bite of your tuna fish sandwich, some say you don’t need to worry about the mayonnaise or relish. In smaller amounts, these ingredients won’t hurt your dog. With most dogs, small amounts of bread won’t pose too many problems either. 

What Kinds of Tuna Are the Safest?

a cute shih poo puppy
A super cute Shih Poo puppy looks up at the camera

If you do have tuna in your house or decide to feed your dog the occasionally fishy treat, some types contain less mercury than others. Skipjack and albacore tend to have less mercury than their counterparts. You can spot skipjack with labels like “chunk light” and albacore will usually be labeled as “white albacore.” 

These types of tuna tend to contain less mercury because they weigh less and don’t consume as many toxins from the ocean. This includes other fish and living species. Tuna that grow larger in size and weight are more likely to contain more mercury and other toxins. 

What About Puppies?

Puppies shouldn’t transition to solid foods, including tuna until they’re at least 4 weeks old. Even then, the number of solid foods they get in their diet should be small. You should gradually introduce solid foods like kibble and raw diets until they’re old enough to tolerate a 100% non-liquid diet. 

Feeding tuna to puppies is usually not recommended because of their lower weights. Similar to small dogs, these lower weights can make them more susceptible to mercury poisoning. It doesn’t take as much to get them sick. Even small amounts can result in permanent damage to their developing systems. 

standard labradoodle wavy brown coat
The golden-brown coat of a tan Labradoodle enjoying the beach

Is Sushi Okay?

In a word, no. Sushi can contain raw tuna and other fish that may be harmful to your pet. Things like parasites are more common in raw meats, including tuna. When parasites get into your dog’s system, they can cause major problems. This includes vomiting, diarrhea, nausea, loss of appetite, and physical weakness.

Some parasites can lower your dog’s iron levels and make it more difficult for their systems to absorb nutrients. Because of a loss of appetite and watery diarrhea, your dog can also become easily dehydrated. It’s best to keep your love for sushi far away from your pet. Be careful when eating and preparing it in your kitchen and dining room. 

scrambled eggs for dogs
The raw vs cooked debate extends well beyond fish for dogs – what about eggs? Can you crack raw eggs into wet food?
Can dogs eat scrambled eggs?

The Final Verdict

Despite some indications that tuna may be okay for your dog in small amounts, we’re recommending you don’t feed it to your pet at all.

It’s better to err on the side of caution than to risk your dog’s short and long-term health.

Given that there are alternatives to tuna for protein, vitamins, and minerals, it’s best to choose these for your dog instead. 

Commercial diets aren’t something that every pet owner will choose. However, each owner should avoid food sources that could poison their animal and always consult their vet.