Is Fish Oil Good For Dogs?

By Adrian Oaks / January 16, 2016

Many pet owners will benefit by adding a fish oil supplement to their pets diet. Dogs, in particular, have been shown to react positively when introduced to supplemental omega 3 fatty acids. Fish oils such as cod liver oil, krill oil, and salmon oil are a great "health maintenance" supplement. Fish oil benefits your dog by helping to treat or even prevent chronic health conditions, such as:

  • Dog arthritis
  • Inflammation
  • Joint problems
  • Auto-Immune conditions
  • Canine allergies
  • General over all pain relief for dogs
  • High Cholesterol
  • Heart, kidney, and eye conditions
  • Dry or irritated skin, dermatitis, rashes
  • Dull and lifeless fur/heavy shedding
  • Memory problems (especially in aging dogs)
  • Cancer

Polyunsaturated fats: Omega-3 and Omega-6

Omega-3 is a polyunsaturated fat found mostly in algae, nuts/seeds, and fish. Your dogs body cannot synthesize this essential fatty acid by itself and can only get it by eating foods high in omega 3 fatty acids or through fish oil supplements.

Omega-6 fatty acid is found mostly in animal products, wheat durum, and vegetable oils.

Commercially made dog foods are high in GLA (an omega 6 fatty acid) and have very low or almost nonexistent omega 3 profiles. Additionally, some pet food products have been shown to cause arthritis in dogs, due to questionable ingredients and manufacturing processes. Often you can purchase commercial kibble foods that are fortified with DHA or EPA to remedy this. Unfortunately it is best to avoid these types of products as fish oil tends to go rancid quite quickly.

Dogs that are raised on an imbalanced diet can develop health problems over time. Some common and easy to spot signs of omega 3 deficiency are:

Fur loss - A classic sign of omega 3 deficiency, fur loss will often be accompanied by heavy scratching to the point of inflammation. A depressed immune system will also result in your dog being more vulnerable to skin mange.

Ear infections - Chronic and persistent ear infections are another telltale sign of omega 3 deficiency.

Weight Gain/Muscle loss – You will notice a loss of muscle as well as a rise in fat.

Although some of these conditions are minor, it is important to remember that there is a difference between a healthy dog and a dog that is on its way to more chronic health problems later on in its life. To prevent these problems it is imperative to ensure your dog is on a balanced diet with an adequate omega 3/6 ratio.

Types Of Fish Oils

There are quite a few different varieties of fish oil on the market. In this section we will take a look at 3 of the most popular types.

Salmon oil for dogs - Although it has a fancy name, salmon oil is just regular fish oil. The important thing to look for is where the salmon is sourced from. Higher quality fish oils will be sourced from wild caught salmon. Cheaper alternatives will use farmed salmon. Farmed salmon are raised in offshore holding tanks and accumulate a lot more toxic buildup over their lifespan.

Cod liver oil for dogs - Cod liver oil is more of a super food than a supplement. It is fortified with many beneficial vitamins that will support your dogs health and protect it from age related chronic illnesses. It is easily the best fish oil for dogs on the market today. Consider looking into a fermented variety for added potency.

Krill oil for dogs - If you are concerned about safety, consider krill oil in lieu of regular fish oil. Krill oil is a good fish oil for dogs due to its naturally low levels of toxins. It is highly digestible, which makes it much more potent than regular fish oil.

Fish Oil Dosage For Dogs

If you are going to consider supplementing your dogs diet with fish oil, you should pay special attention to the EPA/DHA ratio. EPA stands for eicosapentaenoic acid and DHA stands for docosahexaenoic acid. The differences of the 2 are complex and the explanation long winded. It is better to just say that you should stick to as even of a DHA/EPA ratio as possible. Be sure to check the label of the fish oil you are buying. Here is an example:

The above dose is comparable to about 2 cans of salted tuna, pink salmon, or sardines. To give you a better idea of how a fish oil supplement compares to whole food products, here is a quick table:

Fish TypeServing Size - gOmega3 Content - g%DV Fat
Canned Tuna (in oil)146391718
Atlantic Salmon178402334
Flax Seed Oil218116202

Please consult your vet for the best determination of dosage. The general rule is that dogs require about 100 mg of DHA and EPA per 10 pounds of body weight. You should start with about 250 mg (capsule or oil) of fish oil per 1-10 pounds of body weight daily. Be aware that some pets are adverse to eating fish oil capsules, so it may be easier to opt for a liquid form that can be spread onto their meals.

You should notice an improvement after 1 - 2 weeks depending on the strength and purity of the fish oil. If you do not notice a change after this time period consider doubling the dose for a set period of time.

Signs of excess fish oil include indigestion or diarrhea. Fish oil by itself is not toxic, but if you notice these signs be sure to monitor your dog to ensure it is flushing the excess fish oil out of its body fully. Smaller dog breeds may have more difficulty than larger ones.


For maximum safety it is best to stick with oils that use a molecular distillation process. Molecular distillation is a low temperature, industry standard extraction process for removing toxins and heavy metals such as PCBs, dioxins, arsenic, and mercury. Fish oils that use this process are rated at "undetectable" (parts per millions) by the FDA. These will have the lowest amount of contaminants.

Dog vitamins are somewhat of a gray area. There is far less regulation in comparison to human supplements. Due to this, many of the dog supplements on the market can be unsafe or of low quality. Although they are more highly concentrated than the human varieties, the vast majority of them contain preservatives such as rosemary. Rosemary is neurological irritant that can be potentially fatal. Because of this, we recommend using the human based supplements if you are going to give your dog fish oil. This will be safer for your dog in the long run.

Be sure to store your fish oil in a dark and well cooled area. Refrigerating your oil is best (especially for the liquid varieties) and will prolong its shelf life dramatically.

Additional supplements

Glucosamine for dogs - You may want to consider adding a glucosamine supplement to your dogs regimen, especially for dogs with arthritis. Dog glucosamine aids in joint and tissue growth and pairs very well with fish oils. However just like fish oils there has been very little research done on joint supplements for dogs. Recent clinical trials for dog arthritis treatments have shown positive results, especially when paired with other dog joint supplements such as chondroitin. For this reason some veterinarians treating a pet for joint issues will often recommend glucosamine/chondroitin for dogs.

Vitamin E for dogs - Vitamin E can be a beneficial supplement for dogs with skin or immune system issues. when taken orally, it is a potent anti oxidant that will help to eliminate free radicals from your dogs body. However this supplement is best used topically to treat rashes and skin mites. This vitamin has a synergistic effect with other vitamins, such as vitamin C.

Vitamin C for dogs - Dogs suffering from colds or allergies will benefit greatly from a high quality vitamin C supplement. Special care should be taken when purchasing vitamin C as a supplement, as most varieties on the market only contain ascorbic acid. Ascorbic acid is only one small component of vitamin C. In order to get the full benefit from this vitamin it is best to consume it from a whole food source, such as camu camu.

Olive oil / Flaxseed oil for dogs - Flax and olive oils contain a unique type of omega-3 called ALA. ALA is a "small chain" fatty acid that has no benefit by itself, however your dogs body will convert it to EPA/DHA. Flax seed oil contains a compound called lignan that can help reduce the risk of hormone related cancers. The chief benefit of ALA oils over fish oils is that they have a lower contaminate ratio since they don't come from the ocean. Dog owners who prefer to feed their dog a vegetarian diet will find flax seed oil to be an adequate substitute for fish oils.