The Benefits of Giving Your Dog or Cat Fish Oil

Author: Dr. Beth Turner

Published: March 7, 2024

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fish oil capsules for dogs and cats

I am a huge fan of supplements, not just for people but for pets, too!

In my own life, supplements have improved my health and overall quality of life. While the list of supplements I love for pets is long, one of my favorites, next to probiotics, is fish oil (a.k.a. omega fatty acids).

Don’t get me wrong, fish oil isn’t a magic wand that makes all your pet’s problems go away, but I am hoping you will decide it is a helpful and beneficial addition to your pet’s nutritional intake.

Note: Do NOT give your pet fish oil in any form if they have an intolerance or allergy to any kind of fish.


Why Is Fish Oil Good for Pets?

You may be wondering how fish oils are able to help. Well, omega-3 fatty acids, specifically Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA), that are present in fish oils, can help decrease inflammation in not only skin cells but throughout your pet’s body.

When a body is under a state of constant inflammation, regardless of the cause or location, cells suffer microscopic damage and oxidative stress. When this occurs, there is an increased risk of illness and disease.

Guess what? Fish oil benefits don’t end with just reducing inflammation. They also offer potential benefits to other parts of the body and help with different diseases. Studies and clinical experiences also suggest a role for the use of fish oils in managing a host of conditions in pets.

Benefits of Giving Your Pet Fish Oil

This is not a complete list, but these are the known and clinically proven benefits.




  • Fish oil has been found to slow the development (by inhibiting cell growth) and metastasis (spread) of certain cancers, such as lymphoma and mammary tumors.

Cardiovascular System

  • Lowers blood pressure

  • Certain heart conditions, such as atrial fibrillation

  • Heart-failure-associated inflammation can be reduced

  • Helps lower triglyceride levels in the blood, which is important for those dogs suffering from pancreatitis, heart disease, and inflammatory bowel disease

  • In cats with heart disease, it can act as an anti-coagulant and help prevent blood clots

  • Heart-failure-associated muscle loss may be reduced

dog licking at dropper of fish oil

Immune System



Learning and Behavior

cat scratching behind their ear


  • Decreases inflammation and dryness in the skin, which then helps reduce itchiness.

  • Anti-inflammatory effects may help lessen the frequency of hot spots due to allergies.

  • Helps decrease shedding.

  • Improves coat condition, helping it be silkier and shiny.

Respiratory Tract

  • Helps reduce inflammation in the lungs, which can benefit pets with asthma. Read more about asthma in cats.

  • Decreases airway hyper-responsiveness when cats are experimentally affected by allergens.

siamese himalayan cat that suffers from asthma

How to Choose the Best Fish Oil for Your Pet

While the list of the benefits of fish oils is seemingly tremendous, there are some things to consider. Their benefits are impacted by your pet getting the right formulation from a reputable source and at the correct dose. It is important to realize that fish oils are not a stand-alone therapy for any of the conditions mentioned above.

Plus, even though they are generally quite safe, they do have potential negative side effects. For these reasons, it is essential to consult with your pet’s veterinarian so they can determine if the addition of fish oils to your pet’s daily routine will be useful in the management of any conditions your pet may have.

What Type of Fish Oil Should You Give Your Pet?

As mentioned, the benefits of fish oils require that the formulation is correct.

Triglyceride Versus Ethyl Ester Formulation

When buying omega-3 fatty acids, you must be aware if you are buying the triglyceride formulation (the natural one) or the ethyl ester formulation (the manufactured one). The information should be visible on the label.

Avoid using the manufactured ethyl ester formulation of omega-3. The reason you do not want the ethyl ester product, even though it is less expensive, is because its health benefits are inferior. It is less stable, at least 40% lower absorption by the body, and it doesn’t taste as good. It has also been found that this formulation causes dogs to be more ‘gassy,’ and who wants to deal with that? Instead, look for the natural triglyceride formulation of omega-3.

small fish next to fish oil capsulesWhere Is the Fish Oil Sourced?

As with anything that we or our pets consume, you want the source to be reputable and reliable. Over the years, fish oils have grown in popularity in both human and animal health. Therefore, manufacturers have made a lot of claims in regard to their products to boost sales.

Unfortunately, fish oil supplements are not regulated by the FDA. This means that these supplements may not meet their label claims for DHA or EPA and could potentially exceed the recommended amounts.

When evaluating what fish oils to buy, you want to look at some key features:

Purity. Be sure to check the label's Certification of Analysis (CoA). Fish oils can contain heavy metals and other contaminants, especially if they come from polluted waters. Know where the fish were caught for your supplement.

Freshness. Fish oils can easily go bad. This is another reason the CoA is important. The CoA’s anisidine and peroxide values help you know the freshness, which is measured by oxidation. They should be less than 5mEq/kg.

Potency. The product must contain DHA and EPA. If you want to focus on helping your pet's skin issues, such as itchiness, use oil with higher levels of EPA than DHA. The amount of DHA should be higher than EPA if you are trying to support brain health, particularly since it provides the most benefits.

Bioavailability. The fish oil must be in the natural triglyceride form for optimal absorption by the body. Don’t use the synthetic form, which is sometimes labeled as EE-based (ethyl-esters) or sold as omega-3 fish oil concentrate.

Purchase the Right Size of Pills or Chews

If you are purchasing fish oil in capsule or chew form, make sure to buy the appropriate size for your pet instead of dividing or cutting up pills and chews.

Also, not all products are good for both dogs and cats. We've listed our recommended choices separately for you below.

Beware of Flavoring

Flavoring is often added to chews. If your pet has food intolerances or allergies, avoid products with flavoring (beef, chicken, etc.). We've been told by many companies that their flavoring does not cause issues, but some clients of our veterinarians over the years have claimed issues.

fish oil capsulesFish Oil Products That Are Veterinary-Approved

There are potential side effects of taking fish oil that we list below. So, it's best to consult with your veterinarian on the brand and dosage they recommend for your pet.

Here are some recommended products that have been analyzed for purity, accuracy, and safety.

Dog-Only Fish Oil Products





Cat-Only Fish Oil Products




Fish Oil Products For Dogs & Cats

These products are ideal if you have multiple pets and want to use the same product for both. Always consult the dosing amount on the packaging, as it could be very different for a cat or small dog versus a larger dog.




dog and cat eating side by sideHow Much Fish Oil Should You Give Your Pet?

Now you know what formulation to use and what to look for with regard to a reputable source.

The last thing to take into account is the dose. If you under-dose your pet, you will lose the benefits of fish oils and likely be wasting your money.

If you overdose your pet, you can potentially cause harm (read more about the adverse side effects below).

I recommend consulting with your pet's veterinarian in order to calculate the exact dose your pet needs based on their current weight.

Fish Oil Dose for Dogs

For reference, the typical dosing range is 75–100 mg/kg. But typically, the Canine Arthritis Resources and Education suggests 100 mg/kg.

Fish Oil Dose for Cats

Data for therapeutic supplementation of omega-3 is minimal for cats. Retrospective studies suggest a dose of about 112 or 120 mg of combined EPA and DHA per kilogram of body weight.

Only Use Fish Oils Made Specifically for Pets

I cannot stress enough that there are several reasons not to use human fish oil supplements for your pet. They may have added sweeteners such as xylitol, which is highly toxic to dogs and possibly to cats.

We have a regularly updated list of products that contain xylitol, including a few brands of fish oils. Please read labels carefully.

Fish oils formulated for humans may have added flavoring, which can create adverse reactions for those dogs and cats with food allergies. Also, there may be other added ingredients that may not be suitable for pets. For example, some human fish oil supplements contain vitamin D. The commonly supplemented doses of vitamin D can be toxic for a dog or cat.

Potential Adverse Side Effects of Using Fish Oil for Pets

It is important to consult with your veterinarian because while fish oil is generally quite safe, there are some potential adverse effects, especially if the dose is incorrect for your pet.

The following are some things to be aware of when adding a fish oil supplement to your pet's diet:

  • Supplement and drug interactions — such as Anticoagulants, Doxorubicin, and NSAIDs (non-steroidal anti-inflammatory drugs)

  • Vitamin, herbal therapies, and supplement interactions

  • Changes in platelet functions can lead to blood clotting issues

  • Weight gain

  • Vomiting and diarrhea

  • Delayed wound healing

  • Sleepiness

  • Effects on insulin sensitivity

  • Vitamin A overdose can occur

In addition to the above-mentioned potential side effects, you must use caution with pets under the following circumstances:

  • Pre-existing diabetes

  • History of diarrhea

  • Prior history of pancreatitis. This is especially true in Schnauzers and Yorkshire Terriers, both of which are predisposed to pancreatitis.

  • Pregnant or nursing pets

Overall, the benefits of fish oils are tremendous. I highly recommend consulting with your veterinarian to determine how you can safely incorporate them into your pet’s daily routine.

About the author

Profile picture for Dr. Beth Turner

Dr. Beth Turner

Beth Turner is a veterinarian with over 20 years of experience. She graduated from North Carolina State College of Veterinary Medicine and following graduation, she began her career as an associate veterinarian and worked closely with the local shelter.

In 2007 she accomplished her dream of practice ownership, designing and building her own clinic. Another meaningful role, while running her clinic, was serving as her county's shelter veterinarian. This gave her the opportunity to help improve the lives of many animals in her community as well as work with the rescue she loved. She sold her practice in 2019 to move across the country.