Fish Oil for Dogs – Four Reasons to STOP Using It

After receiving my Advanced Canine Nutrition Certificate and continuing with my ongoing education about pet nutrition through Dog Naturally University and Royal Animal Health University, one constant I have found is that INFORMATION CHANGES. 

We have all been told that Fish Oil is great for our dogs and possible your cat as well. And yes, Omega 3’s are critical for your pet’s health, but there are better ways to get them for your pets without using fish oil. 
First, most dogs get too many omega-6 fats in their diet. And feeding higher amounts of omega-6 fats lead to an increase in inflammation in your dog’s body.

This excess inflammation puts your dog at risk. Because chronic inflammation leads to many health issues including:

  • Allergy symptoms
  • Joint pain
  • Diabetes
  • Auto-immune diseases and many more

This is why we need to add omega-3 fats to our dog’s diet. They help balance out those omega-6 fats to reduce inflammation in the body.
So yes, fish oil does contain the omega-3 fats, EPA and DHA, and they are a healthy addition to his diet – but these health benefits are canceled out by the significant downside of fish oils.

Here are four reasons you shouldn’t give processed fish oil to your pets and then some options as to what are better options.

1. Fish Oil Can Cause Disease and Premature Aging

2. Fish Oil Contains Toxins

3. You Could Be Feeding Your Dog Radiation

4. Your Dog’s Fish Oil Is Killing the Ocean

1. Fish Oil Can Cause Disease and Premature AgingEvery time you open your dog’s bottle of fish oil, something bad happens. The omega-3 fatty acids in fish oil are extremely vulnerable to oxidative damage.

When the fat particles in the oil are exposed to oxygen, it’s called oxidation. This is how they break down into smaller compounds, like malondialdehyde (MDA).

And they create oxygen-containing molecules called free radicals. Both MDA and free radicals cause premature aging and disease. This is because they damage proteins, DNA, and other important cellular structures.  This damage is called oxidative stress and it leads to a number of health problems. The most common include gene mutations, cancer, and inflammatory conditions. Which is ironic because you’re giving your dog fish oil to fight against inflammation … not create inflammation!

Most fish oil will be already oxidized before you even buy it. Oxygen leaks through plastic containers and even the gel caps, causing harmful oxidation. And there’s a risk even in glass containers each time you open them. Because as air enters the container, oxidation occurs and the risk of health issues goes up.

Research proves this. A study by Mata et al showed that oxidative damage increases as intake of omega-3 fat increases. And eating fresh, non-oxidized DHA and EPA has been shown to increase markers of oxidative stress in rats.

 2. Fish Oil Contains ToxinsAlthough the fats stored in fish are nicely loaded with omega-3s, fat is also where toxins are stored. And our oceans are becoming more and more polluted by the minute.

Heavy metals like arsenic, cadmium, lead, and mercury are a by-product of our industrial lifestyle. They aren’t easily broken down, and they end up in the environment at low levels, especially in fish and fish oil.
Heavy metals can cause many health issues including:

  • Nervous system dysfunction
  • Blindness
  • Certain cancers
  • Irreversible liver and kidney damage and even death

Along with heavy metals, there are other toxic compounds that accumulate in fish. Polychlorinated biphenyls (PCBs) were banned in 1979 but they’re still found in the oceans and in fish.PCBs can cause skin problems, muscle spasms, bronchitis and nervous system disorders.Dioxins and furans have also been linked to a number of adverse health effects including:

  • Skin issues
  • Liver issues
  • Immune system problems
  • Endocrine and reproductive disruptions
  • And the development of certain cancers

Now almost any fish oil manufacturer will tell you their product is free of the above toxins–but independent lab analyses may say otherwise.
So it’s essential to ask for a Certificate of Analysis (COA) from the manufacturer before you buy any fish oil. But beware a 2010 lawsuit found that even tested fish oils were still found to contain dangerous PCBs.  

3. You Could Be Feeding Your Dog Radiation
In 2011, the Fukushima nuclear power plant was hit by a tsunami and its reactors melted down. This caused radioactive water to seep into the Pacific Ocean. Every day, 300 tons of this radioactive water still seeps into the ocean.

This radiation has now hit the west coast of North America and has contaminated most marine life. Including the salmon that is commonly used for fish oil.

They are testing positive for radioactive particles, such as Cesium-137 and Strontium-90. If you feed Pacific fish or oils, radioactive strontium and cesium can deposit in his bone marrow. And this can lead to bone cancer and leukemia.

Remember even if fish oil manufacturers test their products for safety, you’ll want a COA if you insist on feeding fish oil.

4. Your Dog’s Fish Oil Is Killing the OceanNearly all fish oils are made from fish that are vacuumed up from the oceans. These fish are caught by accident in nets and a by-product of fisheries known as by-catch. This includes many sea creatures, such as whales, dolphins and sea turtles.
It’s estimated that fishery nets kill 300,000 whales, porpoises and dolphins each year. And from 1970 to 2012, their population numbers have been split in half.

Menhaden fish is one of the most sought-after fish for omega-3 fats – and it’s commonly used for pet foods. The menhaden fish are important to the ocean because they eat algae blooms.

And by doing this they keep the ocean waters clean and full of oxygen. An adult menhaden can filter 5,760 gallons of water in one day! This allows sunlight to penetrate the water and aquatic plant life to grow to support the ocean.

But it’s estimated that half a billion menhaden are fished from our oceans every year. This has resulted in dead zones developing – which are areas with a lack of oxygen.

The fertilizers used on crops run off into the oceans and create these algae blooms. But without the menhaden fish, theses algae blooms are killing our oceans.

And the new kid on the block, krill oil, is no better. Krill are the whale’s main source of food – a single humpback whale can eat nearly 5 tones of krill a day. Scientists speculate that krill populations have fallen by 80% since the mid-1970s.

I hope you’re starting to see that your dog doesn’t need fish oil … but the oceans do!So what are some good options to feed your pet to ensure they are getting Omega 3’s in their diet to counterbalance the high amounts of Omega 6’s they eat on a daily basis. 


What is phytoplankton? Phytoplankton are tiny little bundles of algae and bacteria that sustain the entire ocean. Think of phytoplankton as the meadows and forests of the ocean.

Tiny creatures called zooplankton eat the phytoplankton. And then the larger fish eat the phytoplankton and the zooplankton. This helps pass the omega-3 up the ocean food chain.

And phytoplankton are half omega-3 fats by weight! Which is about double the amount found in fish.There are plant sources of omega-3 fats that you can feed. But your dog isn’t able to convert them as well to get the health benefits. That’s why phytoplankton is a great alternative source for omega-3 fats.Phytoplankton molecules are so small that they don’t even need to be digested. They travel right to your dog’s cells and nourish them directly.
And phytoplankton can be grown in filtered water in farms. So you don’t have to worry about heavy metals, radiation, and toxins, or its impact on the oceans.

Phytoplankton does something fish oil could never do. Phytoplankton contains a powerful antioxidant called Superoxide dismutase (SOD). This antioxidant is called the “king of antioxidants. This is because research shows that creatures with high levels of SOD live longer.
So by feeding phytoplankton you can clear up all that free radical damage caused by the fish oils. And phytoplankton offers many other health benefits too—which I will talk about in another article.

ANSWERS FERMENTED FISH STOCKFull of collagen and minerals, their wild, sustainably-caught North Atlantic white fish serves as the perfect fish for bone broth.

Combined with wild-caught, fermented sardines, this formula creates a powerhouse of good bacteria and a biodiverse whole food source, leaving intact all of the complex nutrient relationships.This stock works better than fish oil and is a healthy way to replace probiotics and supplements for joint, enzyme, thyroid, and kidney support.

Changing your pets over to the phytoplankton or fish stock or just starting to add it to their diet is an easy transition for your pets. Please come in and see us. We carry both the Phytoplankton and Fermented Fish Stock.  

Disclaimer –  Kristina McLeskey is not a Veterinarian. These are just general guidelines. If you have any concerns about your pet’s health, please see your veterinarian.