Algal Oil vs Fish Oil in Pet Food: Which One Is Better?

Did you know fish don’t naturally produce Omega-3?

Fish obtain Omega-3 by consuming marine microalgae or smaller marine creatures like krill – who, in turn, get it from microalgae.

That means microalgae is the original source of Omega-3. By going straight to the source, we get a purer form of Omega-3, free from heavy metal contamination commonly found in fish.

It’s also a safer option for pets with fish allergies, as fish is among the top three most common pet allergens. Plus, algae is sustainable and eco-friendly, grown without the environmental harm of overfishing.

Why Omega‑3 Matters in Pet Nutrition

Omega‑3 fatty acids, especially long-chain EPA (eicosapentaenoic acid) dan DHA (docosahexaenoic acid) – play a vital role in feline and canine health.

Unlike some nutrients, pets cannot efficiently synthesise sufficient EPA and DHA from plant-based sources, making dietary supplementation essential. These fatty acids support skin and coat condition, cognitive function, joint comfort, immune modulation, and cardiovascular health in both cats and dogs.

Understanding Omega‑3: EPA, DHA and ALA

Omega‑3s include ALA (alpha‑linolenic acid), EPA and DHA. While ALA derives from plant oils such as flaxseed, pets convert it to EPA and DHA at a very low rate – unreliable and inefficient.

In contrast, EPA and DHA, found in marine sources like fish oil and algal oil – are directly utilizable, making them far more effective for supporting anti-inflammatory pathways, skin and coat health, and cognitive development in growing or ageing pets.

What Is Fish Oil?

Fish oil is extracted from the tissues of oily fish (salmon, sardines, anchovies), and is a traditional source of EPA and DHA. It is a cost-effective option to deliver these fatty acids into pet diets, commonly used in both supplements and fortified foods.

However, fish may accumulate heavy metals (e.g. mercury) and environmental toxins through the food chain, especially larger predatory species . Meanwhile, farmed fish often contain lower ratios of EPA/DHA compared to wild-caught varieties.

What Is Algal Oil?

Algal oil is derived directly from microalgae such as Schizochytrium atau Nannochloropsis, which are the primary producers of EPA and DHA in marine ecosystems.

This marine-based oil is inherently rich in long-chain omega‑3s and can deliver EPA and DHA at concentrations comparable, or even superior to fish oil.

Critically, algal oil is free from ocean-borne contaminants, sustainably produced on land and renewable, making it ideal for pets with allergies or for owners seeking eco-friendly options.

Nutritional Comparison: Fish Oil vs Algal Oil

Safety & Purity: Heavy Metals, Toxins and Contaminants

Fish oil, typically sourced from marine species – can contain trace toxins like mercury, PCBs, and dioxins due to bioaccumulation.

These contaminants pose long-term health risks for pets, particularly when fish from high food-chain species are used.

By contrast, algal oils are cultivated in controlled environments and demonstrate minimal risk of heavy metals or marine toxins, offering superior purity and safety profile.

Sustainability & Environmental Impact

Fish oil depends on wild fish populations – often sourced from overfished stocks. Penyelidikan forecasts that uncontrolled harvesting rates may collapse many commercial fisheries by mid-century.

Algal oil bypasses marine ecosystems entirely, relying on land-based cultivation with significantly lower carbon footprint and no impacts on marine biodiversity.

Satu lifecycle assessment demonstrated up to 40% lower climate impact per unit of algal oil compared to conventional fish oil.

Cost & Accessibility in Pet Products

Fish oil remains more cost-effective due to its established supply chains and scale, while algal oil typically carries a premium price (often 2–3× higher).

However, the health benefits and low risk of contamination of algal oil justify the cost.

Veterinary Perspective & Clinical Research

Veterinarians show growing interest in algal sources. Some vets recommended switching to algal oil for pets with kidney issues to reduce risk of fish oil oxidation and spoilage .

A formal feeding study in Beagles found algal oil (from Schizochytrium) is safe at high doses and delivers DHA/EPA effectively to support long-term health. Another trial revealed algal oil outperforms fish oil in raising serum DHA levels and improving coat quality, with no adverse effects .

Summary

• Fish Oil: Cost-effective but risks contaminant exposure, sustainability issues, and variable quality.
• Algal Oil: Offers clean, eco-friendly, potent EPA/DHA, superior bioavailability, consistent quality, and better acceptance by some pets.

As scientific and ecological demands rise, algal oil becomes not just a viable substitute, but a premium omega-3 choice for pet nutrition.

Bioavailability: How Well Do Pets Absorb It?

Bioavailability refers to how efficiently the body absorbs and utilises nutrients. In fish oil, EPA and DHA are typically present in triglyceride or ethyl ester form, which require enzymatic conversion in the liver for absorption – a process that can be inefficient in some animals.

In contrast, algal oil often contains pre-converted, highly bioavailable DHA, and in some strains (like Schizochytrium), EPA as well. A clinical trial in dogs showed that algal oil raised blood DHA levels as effectively as fish oil, if not more, with improved retention rates.

Shelf Stability and Oxidation Risk

One of the biggest drawbacks of fish oil is its tendency to oxidise – especially when exposed to air, heat or light. Oxidised oils lose efficacy and may even harm pets due to free radical formation.

Algal oil has a significantly higher oxidative stability because of lower unsaturated fat content and purer formulation. Properly stored, high-quality algal oil resists spoilage and retains potency longer than typical fish oil, offering better shelf life in both supplements and food formats.

Ethical Considerations: Animal Welfare & Ocean Ethics

Many pet owners today seek products that align with ethical sourcing and environmental sustainability. Fish oil production often involves massive fishing operations that affect bycatch species like dolphins and seabirds.

Algal oil avoids these ethical pitfalls entirely, as it’s grown in controlled, land-based bioreactors, with zero harm to marine ecosystems or animals. For ethically conscious pet owners, algal oil represents a more sustainable and cruelty-free source of essential fatty acids.

Final Verdict: Which Is Right for Your Pet?

In summary, algal oil delivers all the functional benefits of fish oil – anti-inflammatory action, improvements in skin, coat, joint, heart and cognitive health – without the drawbacks of environmental contaminants and ecological impact.

Many experts now regard it as a viable, and even superior, alternative in pet nutrition.

If you’re focused on cost-effectiveness and tradition, fish oil remains a reliable and accessible source of omega-3s – but it comes with caveats: sustainability concerns, contamination risks, and oxidation issues.

However, if you’re seeking a cleaner, more sustainable, and ethically sourced option – especially for long-term use or for pets with sensitive digestion – algal oil is increasingly the superior choice.

At Grace Cat, we’re committed to giving your pet the very best. That’s why we are incorporating algal oil into our gloow Omega-3 Pet Lick – the first in Malaysia to use algal-sourced DHA.