Is Fish Oil Good For Dogs?

Is Fish Oil Good For Dogs?

Fish oil contains omega-3 essential fatty acids your dog needs. But is fish oil good for dogs?

Here's some information about the benefits of fish oil. But you'll also find out why it may not be the best choice of oil for your dog ... and read about some safer alternatives that will give your dog the same health benefits.

Is Fish Oil Good For Dogs? 

Fish oil does have many benefits for dogs. Omega-3 essential fatty acids play a crucial role in your dog’s health. The most common dietary sources of these are fish oils and some plant oils.

Omega-3s have many health benefits for your dog, including:

  • Maintaining healthy skin and coat
  • Brain and eye function
  • Moderating inflammation
  • Normal hormone regulation
  • A healthy immune system
  • Normal cellular structure and function

Most dog diets don’t contain enough omega-3 fatty acids, because they contain a lot of foods high in omega-6The balance of omega-6 to omega-3 fatty acids is important for health. Too much omega-6 leads to chronic inflammation that can cause chronic problems like arthritis, allergies, autoimmune disease or even cancer. 

Omega-3 fatty acids have anti-inflammatory functions that help reduce the risk of chronic disease. 

Fish oil is a good source of the essential omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

These beneficial omega-3s help the nervous system develop, fight inflammation, and keep the brain and eyes healthy. They promote a healthy coat, improve joint health, and may lower the risk of some cancers. 

Safety Of Fish Oil

Despite these benefits of fish oil for dogs, there are some good reasons to avoid it.

1 Fish Oil Can be Toxic

Environmental toxins accumulate in fat tissue. Fish oils carry the risk of exposure to toxic contaminants, such as PCBs and heavy metals (1). These toxins build up in fish over time due to polluted oceans. They can cause harmful effects, including organ damage, endocrine issues, neurological problems, leaky gut, immune issues, and more.

Pacific fish have also tested positive for radioactive particles, which could pose a cancer risk to your dog.

2. Fish Oil Goes Rancid Easily

Fish oil is unstable and oxidizes easily. So as soon as you open the bottle and expose it to air, it starts to turn rancid. It will likely smell bad (or fishy). And it also produces unstable molecules called free radicals that cause oxidative stress in your dog. Oxidative stress is cell damage that can contribute to problems like joint issues, cognitive decline, cancer, and diseases of the heart, liver, and kidneys.

3. Fish Oil May Have Unexpected Side Effects

Although it offers some health benefits, fish oil can also be harmful when you give too much of it. You also need to make sure your dog doesn't have a health condition that you could make worse by giving fish oil.

Here are some potential side effects of giving fish oil to dogs (2):

  • Bleeding: Fish oil is a natural anticoagulant, meaning it helps prevent blood from clotting. These blood-thinning properties can be heart-healthy ... but they could be a risk for dogs taking certain medications or undergoing surgery.
  • Low Blood Pressure: Fish oil has properties that lower blood pressure (great if your dog has high blood pressure!). But if your dog has normal blood pressure or is on blood pressure medication, you need to be careful.

4. Fish Oil Harms The Environment

Though fish oil is a rich source of omega-3 fatty acids, it comes at a devastating cost to our oceans. In 2018, people used a shocking 22 million tonnes of fish just to produce fish oil and fish meal. Overfishing harms ecosystems that depend on the type of fish used for oil. Only a few fish oil brands use verified sustainable harvesting methods. 

Fish oil used to be considered the best source of EPA and DHA. Now, there are more sustainable, safer ways to ensure that your dog gets the omega-3 fatty acids he needs.

How Do I Choose A Good Fish Oil For My Dog?

If you decide to give your dog fish oil, you need to be very careful which product you buy. Ask the following questions ...

Is It Sustainable?

First, find a sustainable source of fish oil. The best products are from wild-caught, smaller oily fish like anchovies, sardines, and mackerel. Another plus is that these fish are lower on the food chain and contain fewer toxins than large fish.

How Is It Distilled?

Next, find out how your oil is distilled. The best method is triple-phase molecular distillation. The oil is heated under vacuum to remove pollutants like PCBs and mercury. Then the EPA and DHA are separated and converted to triglyceride form. This creates a much more stable fish oil than other methods.

Where Is It Processed?

The best fish oils are processed in Norway. They use smaller fish and have developed the best processes to create mild tasting and pleasant smelling fish oils.

Is It From Wild Or Farmed Fish?

You want to look for fish oil from wild fish. A lot of fish oil is from farmed fish, which is fed pellets made from other fish meals. Because of this, farmed fish contain far more dangerous toxins than wild fish ... including carcinogens like PCBs, dioxins and even banned insecticides. Farmed fish are also polluted with antibiotics that they're given to prevent disease.

What To Avoid

Here are some types of fish oil that it's best to avoid for your dog.

Salmon Oil

It's safest not to give salmon oil, unless you're certain it's wild-caught. Most salmon oil is from farm-raised salmon, which is much lower in omega-3s and higher in omega-6 than its wild cousins. Farmed salmon may also be genetically modified ... and can be contaminated with toxins from the food they get.  Pacific salmon, even though it may be wild-caught, has also been found to contain radiation from the Fukushima nuclear disaster in 2011. 

The best quality salmon oil is from wild-caught Alaskan salmon.

Oil From Larger Fish

Larger fish are higher on the food chain and contain more toxins than smaller fish. Toxins accumulate over time, so larger fish have absorbed more chemicals over their life time. 

Safer Alternatives To Fish Oil for Dogs

You can avoid the risks that come with fish oil with several safer alternatives. Here are some options that are better for your dog, and for the environment:

1. Green-Lipped Mussel Oil

Green-lipped mussels are found in the pristine waters off the coast of New Zealand. They can be sustainably farmed, so they’re an environmentally responsible choice … with all the same benefits. These mussels eat phytoplankton, which can also be sustainably grown.

Green-lipped mussel oil offers 30 fatty acids, including plenty of EPA and DHA. But it has an extra anti-inflammatory omega-3 that fish oil lacks: ETA. Your dog can convert ETA into EPA in the body, so he makes only as much as his body needs. This helps avoid the possible side effects of too much EPA that come with fish oil.

2. Ahiflower Oil

It's a really good idea to add gamma linolenic acid (GLA) to your dog's diet. GLA is an omega-6 oil ... and you may think of omega-6 fats as unhealthy. But in this case, it's not true. GLA brings strong anti-inflammatory benefits for your dog. GLA also regulates hormones and supports your dog's skin and coat. And ahiflower is a great source of GLA (and fish oil has very little GLA).

Ahiflower is a plant oil that's a fully sustainable source of essential fatty acids (3). Just one acre of ahiflower can yield the same amount of omega-rich oil as 40,000 mackerel or sardines. It's high in GLA as well as SDA (stearidonic acid). SDA is a precursor for EPA, one of the important anti-inflammatory omega-3 fats in fish oil.

3. Hemp Seed Oil

Hemp seed oil is another good option for providing an ideal balance of omega-3, 6, and 9 fatty acids. It also contains GLA and SDA (but much less than ahiflower).

4. Phytoplankton

Phytoplankton is a food source that anchors ocean ecosystems. These microalgae are full of nutrients, including EPA. They can be sustainably grown on land and contain a powerful antioxidant, Superoxide Dismutase (SOD). The downside of phytoplankton is that it's very expensive.

5. Algal Oil

Algal oil is a plant-derived oil with a good amount of DHA. Like fish oil, it does not contain GLA or ETA. The main advantage of this oil is that it is a sustainable, plant-based source of omega-3s.

6. Brains And Eyes

Yes, you read that right! You can provide your dog the same nutrients found in fish oil by feeding these organs instead. Just 4 ounces of brain has more DHA and EPA than one teaspoon of fish oil. 

Feeding organs like these also prevents waste by helping use more parts of animals being used for meat in the livestock industry. 

FOUR LEAF ROVER RECOMMENDS: Safe-Sea, a blend of sustainable green lipped mussel oil with ahiflower oil that provides potent anti-inflammatory benefits for dogs. Buy Safe-Sea now >>

Now you know several great ways to give your dog essential omega fatty acids without hurting our oceans and risking his health.


  1. Gordana Vuković et al. Persistent organic pollutants (POPs) in edible fish species from different fishing zones of Croatian Adriatic. Marine Pollution Bulletin, Volume 137, 2018.
  2. Lenox CE, Bauer JE. Potential adverse effects of omega-3 Fatty acids in dogs and cats. J Vet Intern Med. 2013 Mar-Apr;27(2):217-26.
  3. Cumberford G et al. Ahiflower oil: A novel non-GM plant-based omega-3+6 source. Lipid Technology. Vol. 27, Issue 9, September 2015. 

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