Where Can You Find Fish Oil? Essential Sources for Omega-3s

October 24, 2025 •

5 min read

It's a fact that your body cannot produce the essential omega-3 fatty acids EPA and DHA, meaning you must obtain them from external sources. Knowing where can you find fish oil—either from fatty fish or high-quality supplements—is crucial for supporting your heart, brain, and overall wellness.

Quick Summary

This guide details the best food and supplement sources of fish oil and marine omega-3s. It covers various fatty fish, different types of supplements like capsules and liquid oils, and how to select high-quality products. Proper sourcing and understanding product composition are also addressed.

Key Points

Food First: The best sources of fish oil and marine omega-3s are fatty, cold-water fish like salmon, mackerel, and sardines.
Supplements for Gaps: Fish oil supplements are a practical option for those who don't consume fatty fish regularly.
Check the Label: Always look for the specific amounts of EPA and DHA on a supplement label, not just the total fish oil content.
Prioritize Purity: Choose supplements that have been third-party tested for contaminants like mercury and PCBs, evidenced by certifications such as IFOS.
Consider Vegan Options: Plant-based alternatives like algal oil are excellent for vegetarians and vegans as they contain pre-formed EPA and DHA.
Cod Liver vs. Fish Oil: Cod liver oil contains additional vitamins A and D, so be mindful of potential toxicity concerns with excessive intake.
Consistency is Key: For long-term health benefits, taking your chosen source of omega-3 consistently is important.

The Importance of Omega-3 Fatty Acids

Omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are crucial for numerous bodily functions. These polyunsaturated fats are vital for developing and maintaining the health of your heart, brain, eyes, and immune system. Since the human body cannot produce significant amounts of EPA and DHA on its own, it's essential to include them in your diet. While a diet rich in certain marine foods is the ideal approach, supplements offer a reliable alternative for many people.

Dietary Sources: The Bounty from the Sea

The most bioavailable and potent forms of EPA and DHA come directly from seafood. By including servings of fatty fish per week in your diet, you can support your intake of these important nutrients. The best sources typically include cold-water oily fish and certain shellfish.

Here are some of the top food sources for fish oil:

Salmon: One of the most popular and nutrient-dense sources, providing a high concentration of both EPA and DHA. Both farmed and wild salmon are excellent options.
Mackerel: A small, fatty fish often sold smoked, mackerel is exceptionally rich in omega-3s.
Sardines: These small, oily fish are commonly available in cans and contain nearly every nutrient your body needs, including high levels of omega-3s.
Anchovies: Tiny but potent, anchovies are a great source of omega-3s, often used to flavor dishes or as a topping.
Herring: A medium-sized, oily fish that is often canned or pickled and contains high amounts of EPA and DHA.
Oysters: A nutritious shellfish that contains all three major omega-3 types, including ALA.
Trout: Freshwater trout is a good source of omega-3 fatty acids.

When consuming fish, it is important to be mindful of mercury levels, which can accumulate in larger, longer-living fish. Lower-mercury options like salmon, sardines, and anchovies are generally the safest for regular consumption.

Supplement Sources: A Practical Alternative

For those who do not eat enough fatty fish, supplements are a convenient and effective way to increase omega-3 intake. The marketplace offers a variety of products, each with its own characteristics.

Here are the common types of fish oil supplements:

Fish Oil Capsules/Softgels: The most common form, these are concentrated oil extracts from various fatty fish, offering a standardized amount of EPA and DHA. Look for products that list specific EPA and DHA amounts on the label.
Cod Liver Oil: As the name suggests, this oil is derived specifically from the liver of codfish. It is a source of omega-3s but also contains vitamins A and D, which means excessive intake could lead to toxicity.
Krill Oil: This oil comes from small, shrimp-like crustaceans and is rich in omega-3 fatty acids, antioxidants, and nutrients.
Algal Oil: For vegetarians and vegans, algal oil is a marine-based, plant-derived source of DHA and EPA, which is where fish get their omega-3s in the first place.
Liquid Fish Oil: For those who prefer liquids, liquid oils are an option, though they may have a stronger taste. Some are flavoured to mask the fishy taste.

How to Choose a High-Quality Fish Oil Supplement

Since the supplement industry is not strictly regulated by the FDA, choosing a reputable brand is essential. Quality can vary widely, so it's important to look for specific markers of purity and freshness.

Check the EPA and DHA Content: Don't be fooled by the total "fish oil" amount on the label. Look for the specific breakdown of EPA and DHA to determine the true amount per serving.
Look for Third-Party Testing: Reputable brands will have their products tested by independent third-party organizations like the International Fish Oil Standards (IFOS) or NSF International. These certifications verify the product's purity, potency, and freedom from contaminants like mercury and PCBs.
Assess Freshness: Fresh fish oil has a very mild, sea-like smell. A strong or fishy odor indicates the oil has oxidized and may be rancid. Quality supplements protect against this with low-temperature processing and light-proof bottles.
Consider the Form: The form of the omega-3 fatty acid affects its bioavailability. Natural triglycerides (TG) are the most easily absorbed. Some supplements use a concentrated re-esterified triglyceride (rTG) form, which is also highly bioavailable.
Ensure Sustainable Sourcing: Opt for brands that source their oil from small, wild-caught fish with short lifespans, such as sardines and anchovies. Look for certifications from the Marine Stewardship Council (MSC) or Friend of the Sea.

Comparison: Dietary Sources vs. Supplements


Feature	Dietary Sources (e.g., Salmon, Sardines)	Supplement Sources (e.g., Capsules, Oil)
Omega-3 Bioavailability	Excellent; natural triglyceride form is highly absorbed.	Varies by form; natural triglycerides (TG) and re-esterified triglycerides (rTG) are most bioavailable. Ethyl esters (EE) are less so.
EPA & DHA Content	Varies significantly depending on fish type, size, and whether it's farmed or wild.	Standardized and clearly listed on the label for understanding the amount per serving.
Additional Nutrients	Provides a complete package of protein, vitamins (like B12 and D), and minerals.	Can contain additional vitamins (e.g., cod liver oil) but lacks the complete nutritional profile of whole fish.
Potential Contaminants	Larger, longer-living fish like swordfish and king mackerel have higher mercury risk.	Quality, third-party-tested supplements are molecularly distilled to remove heavy metals and pollutants.
Convenience	Requires preparation and cooking; limited options for those with dietary restrictions.	Easy to take daily; wide variety of options for different preferences and needs.

Conclusion: A Balanced Approach to Fish Oil

Whether you choose to get your omega-3s from food or supplements, the key is to ensure consistent intake of EPA and DHA for long-term health benefits. Eating fatty fish two to three times a week can be a good way to get fish oil naturally and receive a wider range of beneficial nutrients. However, for those who don't eat fish regularly, a high-quality, third-party-tested supplement is a reliable and safe alternative. Before starting any new supplement, it is wise to consult a healthcare provider to ensure it's the right choice for your individual needs. For more on the health benefits of omega-3s, the National Institutes of Health provides comprehensive information.

Frequently Asked Questions

Fish oil is typically extracted from the flesh of various fatty fish, while cod liver oil is specifically derived from the livers of codfish. This means cod liver oil contains vitamins A and D in addition to omega-3s, whereas standard fish oil does not.

Yes, fish oil supplements are generally considered safe for most people, especially when taken as directed. Common mild side effects can include heartburn or a fishy aftertaste, which can often be minimized by taking them with food.

Look for the specific concentration of EPA and DHA per serving, not just the total milligrams of fish oil. Also, check for third-party certifications like IFOS or NSF International to ensure purity and freedom from contaminants.

Wild-caught fish and fish oil from small, wild-caught fish (like anchovies and sardines) are generally preferred due to their lower risk of environmental pollutants like mercury and PCBs. Reputable supplement brands test their products to ensure low contaminant levels regardless of the source.

The best time to take fish oil depends on your personal schedule and consistency. Taking it with a meal, particularly one containing some fat, can significantly improve absorption and reduce side effects like acid reflux or 'fishy burps'.

Yes, vegans and vegetarians can obtain EPA and DHA from algal oil supplements, which is derived from marine algae. This is the same source from which fish originally get their omega-3s, and it provides the more beneficial forms of the fatty acids that plant-based sources like flaxseed often lack.

Determining the appropriate amount of fish oil depends on individual needs and health goals. Consulting with a healthcare professional can help you understand the right approach for your specific situation.