Best Fish Oil for Dogs: Six Liquid Picks and How to Choose

Fish oil is a liquid or capsule supplement made from fish. VCA Animal Hospitals says fish oil is a supplement derived from cold-water fish such as salmon, and that it is rich in the omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). The six liquid fish oils below are described from their Amazon listings and, for Welactin, the maker's own page.

VCA says EPA and DHA act as anti-inflammatory agents and are used for inflammatory diseases, including skin allergies and dermatitis and arthritis. VCA also says few supplements have been through rigorous scientific trials, and that a veterinarian is the best source of information about the safety of these products. A dog with itching, flaking skin, stiff joints, or any other health problem needs a vet visit, not a supplement choice from a web page. Read more about salmon oil for German Shepherds.

Best Fish Oil Supplements for Dogs

Zesty Paws Salmon Oil for Dogs & Cats

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Zesty Paws sells this as a liquid in an 8.5 ounce pump bottle for dogs and cats. The listing says to add a few pumps to food and that the oil contains EPA and DHA. The listing title says salmon oil, and the bottle label reads Omega-3 Blend Pollock + Salmon Oil.

Pros

• A pump bottle, so there are no capsules to give
• The listing says it contains EPA and DHA

Cons

• It is made with salmon oil, and VCA says not to use fish oil in animals that are allergic to any component
• The label covers dogs and cats, so use the directions printed for dogs

Nordic Naturals Omega-3 Pet, Fish Oil for Dogs (8oz)

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Nordic Naturals makes this as a liquid for dogs. The listing says it uses the same quality oil as the company's human products but is specially formulated for dogs, and that every batch is made from fresh, wild-caught, omega-rich fish. The listing also says the oils are in the triglyceride molecular form, and tells pet parents to use only Nordic's pet products for a dog or cat, not its human products.

Pros

• The listing says it is non-GMO, gluten-free, and dairy-free, with no artificial colors, flavors, or preservatives
• The listing says the oil is in the triglyceride form, the form naturally found in fish

Cons

• VCA says not to use fish oil in animals that are allergic to any component
• VCA says to measure liquid forms carefully

Native Pet Omega 3 Fish Oil for Dogs

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Native Pet combines wild-caught Alaskan salmon oil and wild-caught pollock oil, and the listing says it was formulated with a board-certified veterinary nutritionist. The 8 ounce bottle has a pump with a locking mechanism, and the listing says each bottle is about a 30-day supply for a typical dog and points to the label for weight-based directions. It also says the oil is made at an NASC member facility.

Pros

• Two fish oils, salmon and pollock, named on the listing
• A locking pump, and the listing sends you to the label for weight-based directions
• Labeled for dogs and cats

Cons

• The listing says it contains salmon oil, and VCA says not to use fish oil in animals that are allergic to any component

Nutramax Welactin Omega-3 Fish Oil

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Welactin comes from Nutramax, which says on its Welactin page that it provides supplements to support joint health, digestive health, skin and coat health, behavioral health, and more. VCA lists Welactin among the brand names of fish oil. Read more about a joint supplement and about joint supplements for German Shepherds.

The Welactin page says one 6 mL scoop contains 1610 mg of total omega-3 fatty acids, and 1330 mg of EPA and DHA together. Its directions say to “Use accompanying scoop to measure appropriate volume of Welactin® Canine and pour over your dog's food according to the chart below.” The bottle comes with a scoop, and the Amazon listing describes pouring it over the dog's food at mealtime.

Pros

• The maker's page gives the EPA and DHA amount in one scoop
• The maker's page says it is recommended for dogs of all life stages

Cons

• It comes with a scoop, not a pump, so you measure each serving

Pet Honesty Omega 3 Fish Oil (32oz)

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At 32 ounces, this is the largest bottle on the page. The listing title says salmon oil, while its bullets say the oil is made from “100% wild caught pollock and cod liver oil” sourced from the cold waters of Alaska, so check the ingredient list on the bottle. The listing says it comes in a pump bottle, is made in the USA, is third-party tested, and that Pet Honesty is NASC certified.

Pros

• A pump bottle for putting the oil on food
• The listing says it is third-party tested and made in the USA
• The largest size here, at 32 ounces

Cons

• VCA says to store fish oil away from light and to follow the maker's storage instructions, including any refrigeration advice

Omega 3 Fish Oil for Dogs (Plano Paws)

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Plano Paws says its Omega 3 Fish Oil for Dogs is made from anchovies, herring, mackerel, and sardines from the ocean waters off the coast of Iceland. The listing calls the oil human grade and molecularly distilled, says it is for all breeds and ages, and says a liquid pump squirts the oil onto food.

Pros

• Four small fish are named on the listing
• A pump, and the listing says to squirt the oil onto food

Cons

• VCA says to use fish oil with caution in pets that are pregnant or nursing

How to Choose Fish Oil for Your Dog

EPA and DHA

These are the two omega-3 fatty acids VCA names in fish oil. A label can list them in two ways, as the Welactin page shows: total omega-3 fatty acids, and EPA plus DHA. The AKC quotes its chief veterinarian, Dr. Jerry Klein, as saying to look beyond omega-3 levels alone, because quality, sourcing, stability, and sustainability matter as well. Because many commercial diets contain ingredients rich in omega-6 fatty acids, the AKC says, some dogs may consume more omega-6 than omega-3. The AKC also says many commercial dog foods already contain fish oil, so review the food label with your vet before you add any.

Liquid, Capsules, and Chews

VCA says fish oil comes in the form of a capsule or liquid and that you should measure liquid forms carefully. The AKC says fish oil products are available as liquids, capsules, and soft chews. It says fish oil supplements generally fall into three categories: natural triglyceride oil, which is the least processed and tends to be the easiest to absorb but may contain contaminants; ethyl ester oil, which is concentrated and distilled to remove impurities; and synthetic triglyceride oil, which is generally considered the least absorbable form. Check the label for the form.

Sourcing and Purity

VCA says not to use fish oil when a reputable source cannot be obtained, because some sources carry a high risk of heavy metal toxicity. The AKC lists independent quality and safety certifications and oil from smaller cold-water fish, which often contain fewer contaminants than larger predatory fish, among the things Dr. Klein recommends considering. The National Animal Supplement Council says its yellow Quality Seal means a supplier passed a third-party audit and keeps up with its quality requirements, and that a company must earn the seal because it cannot be purchased. The Native Pet and Pet Honesty listings mention NASC. The FDA says it regulates products marketed as dietary supplements for animals as either animal food or animal drugs, depending on their ingredients and intended use.

How Much to Give

No amount is given on this page. The AKC says fish oil dosage depends on a dog's weight, age, health status, and diet, and that, rather than relying only on package directions, you should ask your veterinarian how much is appropriate. The Merck Veterinary Manual says many commercial essential fatty acid products may be used at the manufacturer's recommended dose. The AKC also says some dogs have digestive upset when they start fish oil, and quotes Dr. Klein: “Then, increase slowly as needed, following your veterinarian’s instructions and the label directions.”

Safety and Side Effects

VCA lists mild gastrointestinal upset, fishy odor, delayed wound healing, an oily coat, and itchiness or skin flaking as possible side effects. It says to stop giving fish oil and contact a veterinarian immediately for an allergic reaction, abnormal bruising or bleeding, pancreatitis, appetite loss, incoordination, or seizures. VCA says to use fish oil with caution in pets taking anticoagulants, pets with a blood clotting disorder, diabetic pets or those with a history of pancreatitis, pets with diarrhea, and pets that are pregnant or nursing, and names warfarin, doxorubicin, and NSAIDs such as meloxicam, robenacoxib, and carprofen among the medications to use with caution alongside it. The AKC adds that Dr. Klein says long-term fish oil alongside grain-based diets may deplete vitamin E stores, so some dogs could require vitamin E supplementation.

Storage and Shelf Life

VCA says to store fish oil in a cool, dry location, to protect it from light, and to follow the maker's storage instructions, including refrigeration recommendations. The AKC says exposure to heat, air, or light can cause oxidation before the expiration date. It says oxidized fish oil becomes rancid and often develops a stronger, unpleasant odor, and that consuming rancid fish oil may lead to gastrointestinal upset, including vomiting or diarrhea. The AKC says to keep containers tightly sealed and to discard products that smell rancid or have passed their expiration date.

Frequently Asked Questions

Can dogs take human fish oil?

No. The AKC says “Human fish oil products may contain ingredients that are unsafe for dogs, and dosage recommendations are intended for people.” It says to choose a supplement specifically formulated for dogs and to follow your veterinarian's guidance. The Nordic Naturals listing also says to use only its pet products for a dog or cat, not its human products.

How long does fish oil take to work on dogs?

It can take several weeks. VCA says fish oil “may take several weeks before full effects are seen, although gradual improvements are usually noticeable.” A dog with a skin or joint problem needs a vet to look at it first.

Can a dog have too much fish oil?

Large amounts may cause trouble. The Merck Veterinary Manual says large doses of essential fatty acids may cause weight gain or diarrhea, and that pancreatitis has been rarely reported. VCA lists the side effects and the signs that mean stopping and calling a vet in the Safety and Side Effects section above.

Does fish oil help a dog with itchy skin?

It depends on the cause. The AKC says signs such as itching, dandruff, or haircoat changes can also be associated with parasites, disease, allergies, or hormonal disorders, and that a dog with other symptoms such as vomiting or lethargy needs a veterinary examination. The Merck Veterinary Manual says approximately 20% of dogs with allergic pruritus will show some improvement with essential fatty acids.

Is salmon oil or fish oil better for dogs?

Salmon oil is one kind of fish oil. VCA describes fish oil as a supplement derived from cold-water fish such as salmon, and the AKC says fish oil comes from oily fish such as salmon, mackerel, and sardines. Of the six products above, the Zesty Paws label names pollock and salmon, the Native Pet listing names salmon and pollock, the Pet Honesty listing names pollock and cod liver oil, and the Plano Paws listing names anchovies, herring, mackerel, and sardines. Read the label for the fish named, and read more about salmon oil for German Shepherds.

Sources

• VCA Animal Hospitals, Fish Oil
• Merck Veterinary Manual, Essential Fatty Acids for Integumentary Disease in Animals
• American Kennel Club, Fish Oil for Dogs: What to Know
• FDA, FDA's Regulation of Pet Food
• National Animal Supplement Council
• Nutramax Laboratories, Welactin Canine Omega-3 Liquid for Dogs