Five Reasons to Consider Fish Oil Supplementation for Your Dog

“Fish” by Malias on Flicker - CCFish oil is certainly a popular supplement these days for health conscious people. There are many proven benefits, and we now know that many of these same benefits also apply to our canine companions.

What is fish oil?

As the name implies, fish oil is derived from marine animals and is a rich source of omega-3 fatty acids. Animals cannot manufacture these fatty acids on their own; they must be consumed in the diet. For this reason they are often referred to as “essential fatty acids.”

Mackerel, tuna, salmon, sturgeon, mullet, bluefish, anchovies, sardines, herring, trout, and menhaden are all loaded to the gills (pun intended) with omega-3’s, and they are common sources of fish oil supplements. The fatty acids with the greatest health benefits are docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Both are ingredients found on the labels of fish oil supplements.

Five known benefits of fish oil supplementation for dogs

Based on the documented benefits of fish oil, veterinarians recommend its use as a nutraceutical (a food that provides medicinal benefit) for the following common canine maladies.

  1. Arthritis

The anti-inflammatory properties of omega-3 fatty acids are responsible for their therapeutic benefit for dogs with arthritis. In a study of 127 dogs with arthritis, those fed a diet supplemented with omega-3 fatty acids showed significant improvement in their abilities to rise from a resting position, play, and walk. Prescription diets made specifically for dogs with arthritis are heavily supplemented with fish oil.

  1. Inflammatory skin disease

Allergic skin disease and other inflammatory skin conditions have the potential to benefit from the anti-inflammatory effects of fish oil. A study was performed on 16 dogs with itchy skin. Compared to the placebo group, those receiving fish oil demonstrated significant improvement (less itching, less self-trauma, and improved haircoat).

Another study performed on dogs with varying stages of skin allergies demonstrated that fish oil was more effective for dogs who were in the earliest stages of their skin problems compared to those with more advanced disease.

  1. Treatment of canine cognitive dysfunction

Canine cognitive dysfunction is a well-recognized syndrome of older dogs that, in many ways, resembles human dementia and Alzheimer’s disease. The omega-3 fatty acid, DHA, has been shown to improve cognitive dysfunction in affected dogs. Interestingly, DHA appears to slow the progression of human dementia and Alzheimer’s disease.

A study was performed on 142 older dogs with a variety of behavioral abnormalities (disorientation, disrupted sleep patterns, altered interactions with family members, altered activity levels, and loss of house training). During the 60-day period, dogs fed a DHA-supplemented food showed significant improvement in every one of these behavior categories.

  1. Treatment of heart disease

Profound weight loss is a common symptom in dogs with chronic heart failure, and is associated with decreased survival times. A study was performed on dogs with heart failure, some of whom were fed fish oil. The dogs receiving the fish oil supplementation experienced longer survival times and less weight loss compared to those on a fish oil-free diet.

  1. Treatment of kidney disease

Fish oil supplementation has proven benefit in dogs with glomerular disease, a kidney disorder resulting in excessive protein loss in the urine. Glomerular disease is often associated with kidney failure.

In a study of dogs with glomerular disease, dietary supplementation with fish oil was shown to significantly slow the progression of the kidney damage. Additionally, fish oil has been shown to have a protective effect against acute injury to the kidneys. For this reason, fish oil supplementation is reasonable to consider for any dog with compromised kidney function.

Fish Oil Precautions

Let the buyer beware. Not all over the counter fish oil supplements are created equal. In a study of 51 best-selling fish oil products in the United States, 21 of them varied in their DHA and EPA concentrations by more than 10 percent compared to their label claims.

Careful attention to the dose of fish oil for a dog is important. Too much fish oil can produce adverse side effects such as diarrhea, blood clotting abnormalities, delayed wound healing, vitamin E deficiency, weight gain, and altered immune system function. Lastly, fish oil has the potential to produce problematic interactions with some other medications, particularly nonsteroidal anti-inflammatory medications.

Questions for your veterinarian

Thinking of getting your dog started on a fish oil supplement? Before you do, I encourage you to discuss this idea with your veterinarian. Here are some questions to be sure to ask.

  • Does my dog have a disorder that might benefit from fish oil supplementation?
  • What dosage should I give?
  • What brand of fish oil do you recommend?
  • Is fish oil supplementation compatible with the other medications I am giving my dog?

Do you give a fish oil supplement to your dog?  If so, what is the reason?

Best wishes,

Nancy Kay, DVM

Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
Become a Fan of Speaking for Spot on Facebook

Please visit to read excerpts from Speaking for Spot and Your Dog’s Best Health.   There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at,, local bookstores, and your favorite online book seller.

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17 Comments on “Five Reasons to Consider Fish Oil Supplementation for Your Dog

  1. I know of no information pertaining to the benefits of coconut oil in dogs. As with any high fat product fed to a dog, great care must be taken in terms of dosing.

  2. What a great article! I knew fish oil was good for humans but not for dogs. I didn’t realize how many diseases/sickness this could help with. I may have to look more into this. What are you thoughts about giving your dog coconut oil?

  3. I have heard about the potential of overdosing of the fish oil but I really have not found a good article on what amount would be considered too much? I discuss these things with our veterinarian, but I still like to read up on it myself as I have dogs with all kinds of conditions and I give them fish oil and would feel really bad if I hurt them by giving too much.

  4. It sounds like fish oil has a plethora of benefits for your dog, but it’s always a good idea to check with your veterinarian before giving it to them, since they can recommend a brand and dosage. I’ll have to contact my vet when I have to time to look into this a bit more, thanks for sharing!

  5. Hi Helene. Thanks for your comments and question. Please see my response about fish oil to Jane.

  6. I use Iceland Pure Fish oil. I really like it since it comes from non polluted waters and is unscented. My vet only wants me to use the Salmon flavor and it is very important that it be one for dogs and not humans.
    I am using it for my Sweet Lab that has two mast cell tumors. She also needs to be on Benadryal and Pepcid. We took her off the prednisone stetoid because her liver and kidney levels went up. I also use it to help my other lab with itchy skin. I must say her fur is shiny and soft but still itchy from seasonal allergies.
    I have a question about using flaxseed oil. I have been told so many times by different people that dogs do not absorb flaxseed. Is flaxseed oil different?

  7. I do use fish oil for my dog. he has arthritis and itchy skin. It was recommended by my vet. I have heard and read only good things about it so fingers crossed it will help him.

  8. I agree with you Leila. I would be worried about how much salt your dog would be getting with anchovy oil.

  9. Is Anchovies oil OK? I notice how salty anchovies are and I wonder if too much salt in the fish oil would not too good for my dog’s digestive system? Thank you!

  10. Hi Nancy. Thank you for your question. I am always leary of supplying dosages of medications or nutraceuticals for fear of stepping on family veterinarians’ toes. I encourage you to ask this dosage question of your veterinarian.

  11. I have a 90 pound Dobe/Weim mix and a 80 pound Weim/Cathoula mix and both are on fish oil. The EPA is 360 mg and the DHA is 300 mg. Is this sufficient for their size? I find they shed less with this and their coats are soft and shiny. Also no dandruff.

  12. Thanks for your comments Jane. Flaxseed oil is not nearly as good a source for the fatty acid EPA as is fish oil. So, my preference is fish oil.

  13. I would love to have a dog and will when I retire. I now share my life with two beautiful 10 year old cat brothers who are the lights of my life. I give them green lipped mussel powder (human grade) because I believe it is good for their health. I also use a fish oil supplement.

  14. Hi Diane. Good question and I’m not sure of the answer. I recommend checking the label to see if it lists the amounts of DHA and EPA. If not, the next recommended step would be to contact the manufacturer. Lastly, what type of fish is on the ingredient list? Is it one of the species I listed in my article as being good sources of DHA and EPA? Let me know what you learn.

  15. I have been giving my dogs daily fish oil for many years, mostly for skin conditioning, but the other benefits mentioned are definitely a bonus. Fish oil is extremely helpful during the winters when some of my dogs tend to develop extremely dry, flaky skin. I would just like to add that fish oil should be introduced very gradually to avoid gastrointestinal problems and runny stools (take a few days to work up to the recommended dose).