Best Fish Oil For Dogs: Complete Guide

What Should You Look for When Buying Fish Oil for Dogs?

Not all fish oils are created equal. The best fish oil for dogs starts with the source: wild-caught, small, oily fish like salmon, anchovies, sardines, and mackerel. These fish are lower on the food chain, which means they accumulate fewer toxins like mercury and PCBs.

Look for oils that are molecularly distilled. This process removes heavy metals, dioxins, and polychlorinated biphenyls (PCBs) while preserving the beneficial omega-3 fatty acids. A reputable brand will display a Certificate of Analysis (COA) from a third party lab on their website.

EPA and DHA Concentrations Matter

The two key omega-3s are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA is primarily anti inflammatory and supports joint and skin health. DHA supports brain and eye development, especially in puppies and senior dogs. The best fish oil for dogs should list specific EPA and DHA amounts on the label, not just total omega-3s.

Pro Tip: Aim for a combined EPA + DHA level of at least 500 mg per teaspoon for small dogs (under 20 lbs) and at least 1,000 mg per teaspoon for medium to large breeds. Check the label — if the brand doesn’t disclose EPA/DHA separately, skip it.

Form: Liquid vs. Soft Gels vs. Chews

Liquid oils are the most bioavailable and easiest to dose, especially for picky eaters. Soft gels are convenient for travel but require piercing or hiding in food. Chews are less effective because the heat processing can degrade omega-3s. For maximum potency, liquid or soft gels are the the best option.

What Are the Top 5 Fish Oils for Dogs in 2025?

Based on purity, potency, sourcing, and palatability, here are the top contenders for the the right choice this year.

1. Zesty Paws Wild Alaskan Salmon Oil

This is our top pick. It is sourced from wild caught Alaskan salmon, molecularly distilled, and third party tested. Each pump delivers 1,000 mg of omega-3s (575 mg EPA, 425 mg DHA). It comes in a 32 oz bottle with a pump dispenser, making dosing easy. Most dogs love the taste. It is free from artificial preservatives and GMOs.

2. Nordic Naturals Omega-3 Pet Soft Gels

Nordic Naturals is a trusted human grade brand that also makes pet products. Their soft gels are made from wild anchovies and sardines, molecularly distilled, and provide 180 mg EPA and 120 mg DHA per soft gel. They are ideal for dogs with sensitive stomachs because the oil is highly purified. The soft gels can be pierced and squeezed onto food.

3. Grizzly Salmon Oil Plus

Grizzly Salmon Oil Plus combines wild Alaskan salmon oil with pollock oil for a higher omega-3 content. It contains 1,000 mg of omega-3s per teaspoon and is cold processed to preserve nutrients. It is a good budget friendly option without sacrificing quality. It is third party tested for purity.

4. PetHonesty Omega-3 Fish Oil

PetHonesty offers a liquid fish oil from wild caught anchovies and sardines. It provides 700 mg EPA and 500 mg DHA per serving. It is molecularly distilled and comes in a dark glass bottle to protect against oxidation. It also includes vitamin E as a natural preservative.

5. Ultra Oil Skin & Coat Support

Ultra Oil is a blend of wild caught salmon oil, herring oil, and green lipped mussel oil. It provides 1,200 mg of omega-3s per serving. It is particularly good for dogs with skin allergies or dry coats. It is cold pressed and third party tested. The company offers a money back guarantee if your dog doesn’t like it.

Pro Tip: Store liquid fish oil in the refrigerator after opening to prevent rancidity. Rancid oil loses its benefits and can cause digestive upset. Most brands recommend using within 60–90 days of opening.

How Much Fish Oil Should You Give Your Dog?

Dosage depends on your dog’s weight and the EPA/DHA concentration. The general veterinary recommendation is 20–50 mg of combined EPA and DHA per pound of body weight per day. For a 50 lb dog, that means 1,000–2,500 mg of EPA + DHA daily.

Start at the lower end for the first 1–2 weeks, then gradually increase to the full dose. This reduces the risk of loose stools or digestive upset. The the right choice will have clear dosage instructions on the label based on weight.

Signs You Are Giving Too Much

Excessive fish oil can cause diarrhea, a fishy odor on the breath, vomiting, or delayed blood clotting. If you notice any of these, reduce the dose by half and consult your veterinarian. The American Kennel Club (AKC) notes that high doses of omega-3s can also interfere with vitamin E absorption, so some high quality oils include vitamin E.

For more on dosing and safety, see our Ultimate Guide To Dog Health.

Can Fish Oil Help With Specific Dog Health Problems?

Yes, research suggests that omega-3 fatty acids from fish oil can benefit several conditions in dogs. The best fish oil for dogs is often recommended by veterinarians as a complementary treatment.

Joint Health and Arthritis

EPA has strong anti inflammatory effects. A study published in the Journal of the American Veterinary Medical Association found that dogs with osteoarthritis who received a diet high in EPA and DHA showed significant improvement in mobility and reduced pain within 6 weeks. For best results, combine fish oil with glucosamine and chondroitin.

Skin Allergies and Coat Condition

Omega-3s reduce inflammation in the skin, which can help with environmental allergies, flea allergy dermatitis, and dry, flaky skin. Most dogs show improved coat shine and reduced itching within 4–8 weeks. The best fish oil for dogs with allergies should be high in EPA (at least 600 mg per serving).

Kidney Disease

Studies indicate that omega-3s can reduce protein loss in the urine in dogs with chronic kidney disease. The PetMD recommends fish oil for dogs with early stage kidney disease to slow progression. Always consult your vet before starting fish oil if your dog has kidney issues, as dosing is critical.

Cognitive Function in Senior Dogs

DHA is a key structural component of brain tissue. Research suggests that supplementing with DHA rich fish oil can help slow cognitive decline in older dogs, sometimes called canine cognitive dysfunction. You may notice better responsiveness, improved memory for commands, and less confusion within 6–8 weeks. Choose a product with at least 300 mg of DHA per serving for senior dogs.

Pro Tip: If your dog is on blood thinners (like aspirin or NSAIDs), talk to your vet before adding fish oil. High doses of omega-3s can increase bleeding risk due to their anti platelet effects.

Are There Any Risks or Side Effects of Fish Oil for Dogs?

Fish oil is generally safe, but there are risks. The most common side effect is loose stools, especially if you start with too high a dose. Other potential issues include a fishy odor on the breath, vomiting, and delayed wound healing.

Contamination Concerns

Low quality fish oils may contain heavy metals, PCBs, and dioxins. This is why the the best option is always molecularly distilled and third party tested. Avoid oils that don’t disclose their sourcing or testing methods. The ASPCA advises against using human grade fish oils that are not labeled for pets, as they may contain added flavors or xylitol.

Rancidity

Fish oil oxidizes when exposed to air, light, or heat. Rancid oil tastes bad, loses potency, and can cause digestive upset. Always check the expiration date, store in a cool dark place or refrigerator, and use within 60 days of opening. If the oil smells sharp or like paint, discard it.

How Should You Introduce Fish Oil to Your Dog’s Diet?

Introducing fish oil gradually is key to avoiding digestive upset. Start with one quarter of the recommended dose for the first 3–4 days, then increase to half the dose for the next 3–4 days. By day 7, you can move to the full recommended dose if your dog tolerates it well.

Mix the oil directly into your dog’s wet or dry food. For picky eaters, start with a small amount on a treat or a spoonful of plain yogurt. The the right choice will have a mild fishy smell that most dogs find appealing. If your dog refuses the food, try refrigerating the oil to reduce the odor, then mix it thoroughly.

What to Do If Your Dog Gets Diarrhea

Loose stools are the most common side effect when starting fish oil. If this happens, stop supplementation for 2 days, then restart at half the previous dose. If diarrhea persists, switch to a different brand or form (e.g., from liquid to soft gels). Some dogs simply need a lower EPA/DHA concentration to avoid gastrointestinal issues.

Pro Tip: For dogs with very sensitive stomachs, choose a product like Nordic Naturals Omega-3 Pet Soft Gels. The soft gel form releases oil more slowly in the digestive tract, which often reduces loose stools compared to liquid oils.

Can You Combine Fish Oil With Other Supplements?

Yes, fish oil works well with many other canine supplements, but timing and ratios matter. Combining the the right choice with glucosamine and chondroitin creates a powerful joint support regimen. The omega-3s reduce inflammation while glucosamine supports cartilage repair.

Fish oil can also be paired with probiotics. Omega-3s have a mild anti inflammatory effect on the gut lining, which can enhance probiotic effectiveness. However, avoid combining fish oil with high dose vitamin E supplements unless the fish oil already contains vitamin E. Too much vitamin E can cause blood thinning and interfere with clotting. Always give supplements at least 2 hours apart if your dog is on multiple products.

When to Avoid Combining

Do not combine fish oil with other high fat supplements like coconut oil or MCT oil without adjusting total fat intake. Excess fat can cause pancreatitis in susceptible breeds like Miniature Schnauzers. If your dog has a history of pancreatitis, consult your veterinarian before adding any oil based supplement.

Frequently Asked Questions

Can I give my dog fish oil every day?
Yes, daily supplementation is safe and recommended for most dogs. Follow the dosage guidelines on the label based on your dog’s weight. For long term use, choose a high-quality, third party tested oil to avoid toxin buildup.

Is salmon oil or cod liver oil better for dogs?
Salmon oil is generally better because it has a higher ratio of EPA to DHA and is lower in vitamin A. Cod liver oil is high in vitamins A and D, which can accumulate to toxic levels if given long-term. Stick with salmon, anchovy, or sardine oil.

How long does it take for fish oil to work in dogs?
You may notice improvements in coat shine and reduced itching within 2–4 weeks. For joint health benefits, it typically takes 4–8 weeks of consistent dosing. Results vary by individual dog and the condition being treated.

Can fish oil help with my dog’s shedding?
Yes, omega-3s improve skin health and coat quality, which can reduce excessive shedding. Combined with regular brushing and a balanced diet, best fish oil for dogs can noticeably reduce loose hair within 4–6 weeks.

What is the difference between wild caught and farmed salmon oil for dogs?
Wild caught salmon oil has a higher omega-3 content and lower levels of contaminants like PCBs and antibiotics. Farmed salmon oil may contain more inflammatory omega-6s. Always choose wild caught for best fish oil for dogs.

Can puppies take fish oil?
Yes, fish oil is safe for puppies. DHA supports brain and eye development. Use a puppy specific dosage based on weight (usually half the adult dose). Consult your vet for the right amount for your puppy’s breed and size.

Should I refrigerate my dog’s fish oil?
Yes, refrigeration after opening slows oxidation and keeps the oil fresh longer. Most liquid fish oils last 60–90 days in the fridge. Soft gels can be stored in a cool, dark cabinet but check the label for specific instructions.

Can I use human fish oil capsules for my dog?
You can, but it’s not ideal. Human fish oils may contain added flavors, xylitol (toxic to dogs), or excessive vitamin A. They also lack pet specific dosing guidelines. It is safer to use a product labeled for dogs.