Fish Oil For Dogs: Risky or Beneficial?

Fish Oil For Dogs: Risky or Beneficial?

Amy Thompson

Fish oil for dogs is a topic that often sparks debate and confusion among pet owners and veterinarians alike. While some swear by the benefits, others have had negative experiences with fish oil supplements, leaving them unsure about safety and effectiveness.

Headlines like “I almost killed my dog with fish oil products” only add to the uncertainty. Despite this, many people continue to explore fish oil as a potential supplement for their dogs, intrigued by its potential benefits.

So, is fish oil good for dogs? The truth is, it can be both beneficial and problematic.

Fish oil is a popular source of omega-3 fatty acids, which are essential for maintaining your dog’s health. However, it’s important to weigh the benefits against the potential risks and drawbacks.

There are many advantages and disadvantages to consider when you make a decision to use fish oil for your dogs.

Benefits Of Fish Oil For Dogs

Fish oil is a well-known source of omega-3 fatty acids, which play a crucial role in balancing the omega-6 fatty acids in your dog's diet. These omega-3s are essential because they support various aspects of your dog's health, from the skin and coat to the brain and heart.

Balancing Omega-6 And Omega-3 Fatty Acids

Dogs often consume diets high in omega-6 fatty acids due to processed foods. While omega-6 is important, too much of it can lead to health problems. Introducing omega-3 fatty acids helps maintain a healthier balance.

EPA And DHA: Essential Fatty Acids In Fish Oil

Fish oil provides two key omega-3 fatty acids: EPA (eicosapentaenoic acid) and DHA fatty acids (docosahexaenoic acid). These are considered essential because your dog’s body cannot produce them in sufficient amounts and must obtain them through diet. Although dogs can convert some omega-3s from plant sources into EPA and DHA, the process is inefficient, making dietary sources crucial.

Benefits Of EPA And DHA

EPA and DHA offer numerous health benefits for dogs:

  • Support Brain Health: These fatty acids are vital for cognitive function and brain development.
  • Promote Nervous System Development: DHA is particularly important for the development of the nervous system in puppies.
  • Support Skin and Coat Health: Omega-3s help maintain a healthy skin barrier and reduce itchiness.
  • Maintain Eye Health: DHA supports retinal health and overall eye function.
  • Support Joint Health: Omega-3s contribute to joint flexibility and comfort.
  • Assist in Reducing Certain Cancer Risks: EPA and DHA have properties that may lower the risk of developing some cancers.
  • Promote Gut Health: They support a balanced gut microbiome, which is essential for overall health.

Consequences Of EPA And DHA Deficiency

A lack of EPA and DHA in your dog’s diet can lead to various health issues, including:

  • Dull or Poor Coat: A lack of essential fatty acids can result in a less shiny and healthy coat.
  • Dry or Flaky Skin: Insufficient omega-3s can cause dry and flaky skin.
  • Allergies: Deficiencies can exacerbate allergic reactions.
  • Slow Wound Healing: Omega-3s support the immune response and healing processes.
  • Ear Infections: Chronic ear problems can be a sign of an imbalance in fatty acids.
  • Hot Spots: Skin conditions may worsen without adequate omega-3s.

Understanding these benefits and risks helps highlight why fish oil can be an important supplement for your dog, provided it is used appropriately. But before you decide to incorporate fish oil into your dog’s diet, it's essential to understand the potential drawbacks and alternatives.

Drawbacks Of Fish Oil For Dogs

While fish oil has many benefits, there are also significant drawbacks to consider. Understanding these potential issues is crucial for making an informed decision about including fish oil in your dog’s diet.

Missing Important Healthy Fats

Fish oil, while rich in EPA and DHA, lacks other important fatty acids that contribute to overall health. For instance, eicosatetraenoic acid (ETA) is another omega-3 fatty acid that supports joint health and cartilage maintenance.

ETA can be converted to EPA, but not vice versa, making it an essential component that fish oil doesn't provide.

Gamma-linolenic acid (GLA), an omega-6 fatty acid, supports skin and coat health and hormone balance. GLA is found in plant oils, not in fish oil, which means your dog might miss out on these benefits if relying solely on fish oil.

Potential Toxins In Fish Oil

The oceans are increasingly contaminated with heavy metals and pollutants, which accumulate in fish and, consequently, in fish oil. These toxins include:

  • Heavy Metals: Arsenic, lead, mercury, and cadmium can cause significant health issues such as organ damage, neurological problems, and immune system disruption.
  • Polychlorinated Biphenyls (PCBs): Industrial chemicals that can increase cancer risk and cause developmental problems.
  • Dioxins and Furans: Persistent environmental pollutants that can disrupt hormones, harm the immune system, and increase cancer risk.

To minimize these risks, it’s crucial to choose high-quality fish oil and ask for a Certificate of Analysis (COA) from the manufacturer to ensure it’s free from contaminants.

Risk of Oxidation

Fish oil is highly prone to oxidation, which can make it rancid and produce harmful free radicals. These free radicals can damage your dog’s cells, proteins, and DNA, leading to premature aging and chronic diseases such as heart disease, liver disease, and cognitive decline.

To prevent oxidation, always buy fish oil in dark glass bottles and store it in the refrigerator. Gel caps can be stored in the freezer to extend their shelf life.

Environmental Concerns

The production of fish oil has a significant impact on marine ecosystems and cold water fish. Industrial fishing practices often result in bycatch, where non-target species like dolphins and whales are accidentally captured.

Additionally, fish used for fish oil, such as menhaden and anchovies, play crucial roles in the marine food chain. Overfishing these species can disrupt the balance of ocean ecosystems. Choosing sustainably sourced fish oil is essential, but it can still have a negative environmental impact.

Potential Fish Oil Side Effects For Dogs

High doses of fish oil can lead to several side effects in dogs, including:

  • Blood Sugar Issues: High doses of omega-3 fatty acids can increase blood glucose levels, which is problematic for diabetic dogs.
  • Bleeding Risks: Fish oil can thin the blood, increasing the risk of bleeding and hemorrhagic stroke.
  • Low Blood Pressure: Fish oil can lower blood pressure, which can be risky for dogs with normal or low blood pressure, especially if they are on medication.
  • Digestive Upset: Some dogs may experience diarrhea or other digestive issues from fish oil, particularly at high doses.
  • Acid Reflux: Fish oil can cause acid reflux, leading to discomfort and digestive disturbances.
  • Vitamin A Toxicity: Cod liver oil, a type of fish oil, is high in vitamin A, which can be toxic in large amounts.

Given these potential drawbacks, it’s clear that while fish oil has benefits, it also comes with significant risks. Luckily, there are alternatives that can provide your dog with essential omega-3 fatty acids without these downsides.

Alternatives To Fish Oil For Dogs

Fortunately, there are several alternative sources of omega-3 fatty acids that can offer the same benefits as fish oil without the associated risks. These alternatives can support your dog’s overall health while being safer and more sustainable.

Green Lipped Mussel Oil

Green lipped mussel oil, derived from mussels native to New Zealand, is an excellent source of omega-3 fatty acids. This oil is rich in EPA, DHA, and ETA, making it a comprehensive option for supporting joint health and overall wellness.

Unlike fish oil, green lipped mussel oil contains phospholipids, which enhance its bioavailability and make it more effective. Additionally, green lipped mussels are sustainably farmed, minimizing environmental impact.

Benefits of Green Lipped Mussel Oil:

  • Contains a broader spectrum of omega-3 fatty acids, including ETA
  • High bioavailability due to phospholipids
  • Sustainably sourced from clean waters

Ahiflower Oil

Ahiflower oil is a plant-based omega-3 source that has gained popularity for its high content of stearidonic acid (SDA), a precursor to EPA. Ahiflower oil also contains GLA, an omega-6 fatty acid that supports skin and coat health.

As a sustainable plant oil, ahiflower provides a balanced omega-3 and omega-6 profile, making it an excellent choice for dogs.

Benefits of Ahiflower Oil:

  • High in SDA and GLA
  • Balances omega-3 and omega-6 fatty acids
  • Environmentally friendly and sustainable

Algal Oil

Algal oil is derived from marine algae and is a rich source of DHA. While it contains less EPA compared to fish oil, algal oil is an excellent option for supporting brain and eye health. As a plant-derived oil, it is free from the contaminants commonly found in fish oil and is a sustainable choice.

Benefits of Algal Oil:

  • Rich in DHA for brain and eye health
  • Free from marine contaminants
  • Sustainable and suitable for vegetarian diets

Hempseed Oil

Hempseed oil is another plant-based alternative that offers a balanced omega-3, omega-6, and omega-9 fatty acid profile. It contains GLA, which supports skin health and helps maintain a healthy coat. Hempseed oil is also rich in antioxidants, making it a nutritious addition to your dog’s diet.

Benefits of Hempseed Oil:

  • Balanced omega fatty acid profile
  • Contains GLA for skin and coat health
  • Rich in antioxidants

Choosing The Best Omega-3 Supplement For Your Dog

When selecting an omega-3 supplement for your dog, consider factors such as bioavailability, sustainability, and the presence of additional beneficial fatty acids.

Plant-based oils like ahiflower and hempseed oil offer balanced omega profiles and are environmentally friendly options.

Green lipped mussel oil provides a comprehensive range of omega-3s with high bioavailability, making it an excellent choice for dogs with specific health needs.

Key considerations:

  • Look for supplements with a balanced omega-3 and omega-6 profile.
  • Ensure the source is sustainable and free from contaminants.
  • Consider the specific health needs of your dog and choose an oil that supports those needs.

Final Thoughts On Fish Oil Supplements For Dogs

While fish oil has long been touted for its health benefits, it also comes with significant risks and environmental concerns.

So instead of asking "how much fish oil should I give my dog?" it may be best to avoid fish oils in supplement form altogether. The fish oil benefits simply aren't worth the risk.

Fortunately, there are several alternative sources of omega fatty acids that can provide your dog with the necessary nutrients for optimal health.

Green lipped mussel oil, ahiflower oil, algal oil, and hempseed oil are all excellent options that offer the benefits of omega-3s without the drawbacks of fish oil. By choosing these alternatives, you can support your dog’s health in a safer and more sustainable way.

If you do still decide to feed fish oil supplements to your dog, make sure it is specially formulated for dogs, and not human fish oil supplements.


Can you give a dog human fish oil? While you can give a dog human fish oil, it's important to choose a natural triglyceride formulation for optimal absorption and monitor for any stomach upset. Green lipped mussels, ahiflower and hemp seed oils are much better options for both your dog, and the environment. 

What type of fish oil is best for dogs? The best option is to skip the fish oil and try an alternative that contains green lipped mussels and ahiflower. 

How often should I add fish oil to dog food? Fish oil should be added to your dog's food daily, but consult with your veterinarian for the appropriate dosage to avoid potential negative effects and ensure optimal absorption.

How much omega-3 should I give my dog? The amount of omega-3 you should give your dog depends on their body weight; generally, 75-100 mg per kg of body weight is recommended to support heart health.