Can Dogs Eat Fish?

If you’ve ever walked down the dog food aisle of your local pet supply store, you’ve likely realized that fish is frequently on the menu for many canine companions. But can dogs eat fish? Don’t take the bait! Just because it is an ingredient in dog food does not necessarily mean that dogs can safely eat any type of fish that we could offer them. If you want to add fish to your dog’s diet, read this article first!

Dr. Jess describes the benefits and the risks of feeding fish to your dog, as well as which types of fish dogs can eat, and which are best left out of their bowl.

Dog food companies commonly use fish as one of their many ingredients.

However, dog food experts have arguments regarding the safety of serving fish to dogs.

Topics such as an increase in the risk of mercury poisoning, hypernatremia, as well as thiamine inactivation are a few of the concerns of many experts.

Well, is fish really a health threat to the dogs or are we overthinking this? Let me, the veterinarian, explain my thoughts…

It’s always best practice to double-check which foods your dog can and can not eat because many foods that are completely safe and healthy for humans are actually very risky for dogs to eat, or even poisonous or deadly to them.

That’s why I am so glad that you are here making an informed decision before feeding your dog this fish feast!

If you missed it, check out my article on if dogs can eat different forms of tuna fish here!

What Do Dogs Eat?

Some dogs aren’t too picky about what they eat. They’ll eat whatever you try to give them- they’re like vacuum cleaners sucking up anything put in front of them!

Some dogs are pickier than others. Pickier pups can be harder to properly feed because they just won’t swallow any food we try to give them. Try feeding a picky dog something like okra!

A common pet canine diet consists of a complete dry or wet feed and possibly supplements in some specific cases (not all pet dogs need supplements however).

There is also foraging if the dogs are allowed to roam or are feral, and of course there are treats!

The diet of every dog breed can very and is important to know when offering food to your dog.

An improper diet could put your dog at risk of having problems properly digesting their food and absorbing nutrients correctly. And we don’t want that now do we???

So let’s talk specifically about fish and how it could affect your dog’s diet and overall health.

Fish Nutrition Basics:

Fish in general is low in fat, and high in omega-3 fatty acids and vitamins (especially B vitamins) and important minerals.

Do Dogs Like Fish?

Dogs are natural carnivores. Most dogs like the taste of meat and meat products.

The flavor of fish is usually a delicious one for most dogs too.

So yes, most dogs like the taste of fish.

Can Fish Be Harmful to Dogs?

There is an ongoing debate about whether or not it is safe and okay for dogs to eat fish.

Some vets and pet nutritionists say that dogs can eat fish and be healthy and happy – no worries. Other pet experts say the opposite – they are against feeding fish to dogs. 

Then there are even others who suggest feeding only small amounts of fish to dogs- it is okay every once in a while.

Before we can decide whether fish is safe to feed our dogs, we need to first understand some of the risks involved if we do feed our dogs fish.

There are 3 major reasons why many experts say that you should not feed your dog fish. These three big factors include:

Harmful Reason #1: High Mercury Levels

The #1 reason pet health experts have this fish debate is the research showing or suggesting high levels of mercury contained in some fish.

Certain fresh fish, such as tuna, king mackerel, and swordfish, have much higher levels of mercury than other types of fish, such as flounder, salmon, or tilapia. Skipjack and albacore tuna are the two tuna types that contain the least amount of mercury in the tuna family, so if you must feed tuna, look for one of those two varieties.

Why do certain fish contain so much mercury compared to other types of fish caught and sold for consumption?

Industrial pollutants, such as coal plants for instance, leak mercury, and that mercury then flows into lakes, rivers, and oceans.

Once in the water, it can be comsummed by the aqualife, and therefore can be seen accumulating in fish too.

The larger the fish and the older it lives to be, the higher the concentration of mercury in its tissues.

Tuna can live longer and have the potential to grow bigger in comparison to other edible fish, allowing for an increase in mercury levels to accumulate inside the fish’s meat.

If you feed your dog fish that contains mercury, there will be the potential for mercury poisoning, especially if fed large amounts for a long period of time.

Mercury poisoning can kill your dog if physical signs are not noticed and the pup is not treated quickly.

Symptoms of Mercury Poisoning in Dogs

• Anxiety or nervousness
• Loss of coordination
• Diarrhea (watery or bloody)
• Emesis (vomiting) blood
• Tremors
• Kidney damage (inability to urinate, abdominal swelling, shaking, whimpering)
• Loss of feeling in paws
• Hair loss
• Blindness

If you notice these symptoms in your canine companion, contact your local veterinarian immediately.

Harmful Reason #2: Parasites and Contamination

Just like when preparing fish to serve your human family, you should always properly cook the fish thoroughly before feeding it to your dog in order to avoid any issues with ingesting parasites.

Parasites commonly found in fish meat are normally killed by heat during the cooking process, which is the main reason why it is so important to properly cook your fish!

Harmful Reason #3: Thaminase and Vitamin B1 (and even salt!)

One big reason for many to be concerned about feeding dogs certain fish species like tuna, is the enzyme thiaminase.

Any raw fish, no matter what species of fish it is, contains an enzyme called ‘Thiaminase‘.

This enzyme is responsible for breaking down any thiamine (vitamin B1) your dog ingests, but if you properly cook the fish before eating it, the heat from cooking will make this enzyme useless in this regard.

Fish features another health threat for dogs due to it’s high concentration of another factor – sodium.

Many fish live in salty waters and their meat can absorb the salt (sodium chloride), meaning that much of the fish available to us to eat may be high in sodium.

Having a buildup of sodium in your dog can lead to them having hypernatremia (too high sodium concentrations), which can lead to serious illness.

That being said – one can of fish will not lead to this diagnosis!

Your dog would need large amounts over quite a long period of time to this this condition come to fruition.

Allergic Reaction to Fish:

A dog can develop an intolerance or an allergy to any food, so there is always the possibility that your dog is allergic to fish.

If you suspect your dog is allergic to fish do NOT feed fish to your dog.

If your dog is allergic to fish and accidentally ingests it, go to your nearest animal emergency room immediately.

Can Dogs Eat Fish?

Fish, given in small amounts periodically, is most likely just as healthy for your dog as it is for you.

Therefore, yes, dogs can eat fish. 

Moderation is key; never go overboard when feeding fish for dogs. Small amounts every once in a while is okay for most dogs.

Dogs can have fish but only one or two times per week in small, controlled amounts.

Is Fish Beneficial For Dogs?

Fish has several health benefits for dogs, just as it does for humans, discussed earlier in this article. Some of the benefits for your dog include:

• Fish is a great meat and protein source.
• Not only does fish contains high levels of protein, but it contains high levels of healthy fats, minerals and vitamins too.
• Fish is high in Omega-3 fatty acids which can help make your dog’s skin and coat silky, shiny, and smooth.
• Fish is also extremely beneficial for overall development and function of many of the body’s systems due to the great source of many vitamins and minerals found within it.

Types of Fish Dogs Can Eat:

Fish types considered by many to be safer for dogs than tuna are the fish most commonly used in commercial dog foods – salmon, whitefish, herring, flounder, and Arctic char.

Typically, smaller, younger, wild-caught fish are generally safer options when considering adding fish to your dog’s diet.

Salmon:

Salmon is high in omega 3 fatty acids which may help to reduce inflammation in the body. Salmon also contains vitamin B12, selenium and is typically lower in heavy metals compared to other fish. Salmon is best if it is wild caught, as farmed salmon may contain chemicals.

Just do NOT feed your dog smoked salmon! Smoked salmon is not safe because the smoking process involves curing the fish in brine with salt, lots and lots of salt. That makes it too salty for dogs.

Other types of fish like salmon, for instance, feature the same nutritional benefits of tuna, but with a decreased risk of mercury poisoning.

Sardines:

Sardines are small and low on the food chain. They contain minimal amounts of mercury in comparison to larger fish, making them less of a toxin threat.

White Fish:

Lean fish like cod and haddock are a great source of protein and B vitamins.

Atlantic Mackerel:

A good source of omega-3 fatty acids, Atlantic mackerel is also lower in mercury than other types of mackerel like King Mackerel, so it’s safer for your dog to eat.

Can Dogs Eat Canned Fish?

Canned fish can be a healthy, protein-packed snack for your dog.

If feeding your pup canned fish, make sure to look for fish in water rather than oil, and if offering your dog the canned fish water, be sure that the fish does not have any added salt.

Look for the phrase “no salt added” on the can’s packaging just to be sure.

Can Dogs Eat Raw Fish? 

Can dogs have tuna that hasn’t been cooked or isn’t canned?

Hard no. Not only should dogs not eat raw fish but your canine friend should not eat any type of raw fish or seafood.

Raw fish is definitely not the safest choice.

Raw fish can carry bacteria and parasites that may be damaging to the body once consumed.

Also remember that raw fish contains the enzyme thiaminase, and enzyme that can inactivate thiamin (vitamin B1) in your dog’s body.

Cooking fish takes care of this issue, destroying the thiaminase.

Your pup will likely love his fish treat no matter what form it comes in so better to be safe and only serve them cooked fish if any at all!

Can Dogs Eat Breaded or Battered Fish? Can Dogs Eat Fish Sticks?

Unnatural, greasy coatings definitely aren’t safe for your dog to be ingesting. Stick to fresh varieties of fish from the fish counter of your grocery store, and don’t try slipping your pup any fish sticks.

How to Serve Fish to Dogs:

As convenient as it might be to just let your dog have fish, that’s not the safest option for your pup.

Keep the following in mind when serving fish to your dog:

• When buying dog food like canned fish, remember to buy the water-based cans of tuna (not fish in oil!) without additional flavorings or seasonings.
• Try to find a fish that has lower potential for increased mercury levels to avoid any chance of mercury poisoning.
• Make sure to properly cook the fish to eliminate any parasites and harmful bacteria that may be present.
• You can try to steep the fish in water overnight to get rid of as much salt as possible before cooking and serving it to your dog.
• Using fresh fish? Feed cooked fish to your dog with it first deboned. Dogs aren’t great with bones and the bones can end up lodged in their air passage and present as a choking hazard for them.
• Do not add salt or seasonings to the fish. Your dog will love the fish just fine without any additives that could cause them more harm than good.
• Introduce fish small amounts at a time. It’s definitely a good idea to take it slowly. Give your pup a little at a time and wait to see how they react to the treat before proceeding with giving them another bite or two.

And remember that dogs need more than a bowl or plate of fish – they need a complete and balanced diet.

Whichever food you choose for your dog, whether it is fish or another protein source, fresh meat or store-bought kibble, it needs to have the AAFCO label indicating the diet is complete and balanced for your dog’s life stage.

AAFCO approved foods have gone through testing and compliance to make sure that the diet is safe and healthy for your pet.

Dogs already get everything that they need from their kibble or canned food.

How Much Fish Can My Dog Have?

Can dogs eat fish? As I mentioned previously, it depends…  

Small amounts of cooked or canned fish don’t contain enough mercury to cause a problem in your dog if given periodically.

Adult dogs should not eat cooked or canned fish more than once or twice a week, in small amounts.

There is a big difference between feeding your dog fish occasionally as a treat and making it a staple part of their diet. Treat fish as a every-one-in-a-while special treat.

It’s always better to be safe than sorry!

Too much of a good thing can be an issue. Too much fish can lead to obesity and other health problems.

Talk to your vet about the appropriate serving size of fish for your dog, ESPECIALLY if you plan to feed fish as a regular part of their diet.

Can Puppies Eat Fish?

I would never advise a puppy owner to feed this fish to their puppy. No way.

Your pup’s first months of life should consist of specialized puppy diets approved by your local veterinarian upon puppy exam.

Seafood Takeaway:

Dogs are carnivores that really love to hold true to that label!

They LOVE meat! Fish, a meat that is commonly consumed by humans is naturally drool-worthy to our canine companions.

Allowing your pet to have a bite or two of cooked or canned (in water) fish without seasonings, oil, flavorings, or bones, given every once in a while is okay.

Giving your dog a fishy treat every once in a while will not give them mercury poisoning or the other health issues that were discussed throughout this article.

If you are concerned about feeding your pet dog a fish snack or you feel that the fish that they have already snacked on didn’t go well, contact your veterinarian for more guidance on what to do next.

Trust me, us vets are happy to help!

References Used in This Article:

• FDA, “Mercury Levels in Commercial Fish and Shellfish” U.S. Food and Drug Administration (FDA), 2017.
• Sheer, R., et al, “How Does Mercury Get Into Fish?” Scientific American, 2018.
• Mataljan, G., “Tuna: Nutritional Content,” World’s Healthiest Foods, 2018.
• Pendergrass, J., DVM, “Mercury in Dog and Cat Foods: Cause for Concern?” American Veterinarian, 2016.

The information provided in this article is not a substitute for professional veterinary help.