What is the number one healthy fish in the world?

October 25, 2025 •

4 min read

According to the American Heart Association, consuming at least two servings of fatty fish per week significantly benefits heart health due to high omega-3 content. Determining the number one healthy fish, however, is a complex question without a single definitive answer, as several species stand out for their exceptional nutritional value and safety profile.

Quick Summary

This article explores the top contenders for the healthiest fish, focusing on their omega-3 content, potential mercury levels, and overall nutritional profile. It compares salmon, sardines, and mackerel to help readers make informed dietary choices for optimal health.

Key Points

Wild-Caught Salmon Reigns: Rich in omega-3s, protein, and vitamins like B12 and D, wild salmon is a nutritional powerhouse with relatively low mercury levels.
Sardines Offer Unmatched Safety: As small, low-mercury fish, canned sardines provide excellent omega-3s, protein, and bone-boosting calcium, making them a safe, affordable option for frequent consumption.
Mackerel is a Great Alternative: Smaller Atlantic mackerel offers high levels of omega-3s, B12, and selenium, but consumers should be wary of larger species like King mackerel due to high mercury.
Omega-3s Benefit Overall Health: The long-chain omega-3s (EPA and DHA) found in fatty fish are crucial for fighting inflammation, lowering blood pressure, and supporting brain and heart health.
Prioritize Low Mercury and Sustainability: For optimal health and environmental responsibility, choose smaller, low-mercury fish like salmon and sardines, and look for certifications from organizations like the Marine Stewardship Council (MSC).
Variety is Key: The best approach is to include a variety of healthy, low-mercury fish in your diet to get a broad spectrum of nutrients and prevent overconsumption of any single type.

The Case for Salmon: A Nutrient-Dense Champion

When considering what is the number one healthy fish, wild-caught salmon is almost always at the top of the list for good reason. A nutritional powerhouse, salmon is exceptionally rich in omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fatty acids are critical for reducing inflammation, lowering blood pressure, and supporting brain function. Wild salmon contains more protein and slightly fewer calories than farmed varieties, though both are excellent sources of nutrients.

Beyond omega-3s, a 3.5-ounce serving of wild salmon provides over 100% of the Daily Value (DV) for Vitamin B12, crucial for nerve health and red blood cell production. It is also high in selenium, which supports thyroid function and has antioxidant properties. Furthermore, wild sockeye salmon is rich in astaxanthin, a powerful antioxidant that gives the fish its vibrant red color and offers benefits for heart, brain, and skin health. The overall nutritional profile, combined with its relatively low mercury levels compared to larger fish, makes salmon a highly recommended choice.

Potential Drawbacks of Salmon

While a leader in nutrition, salmon has some considerations. The sustainability of some salmon populations, particularly wild Atlantic salmon, is a concern, though sustainably managed farmed and wild Alaskan salmon are widely available and recommended. The sourcing, whether wild or farmed, impacts the nutritional and environmental profile, so it is important to choose responsibly sourced options.

The Dark Horse Contender: Tiny Sardines

Often overlooked, sardines are a powerful contender for the title of healthiest fish. These small, oily fish are packed with nutrients and offer unique advantages. Since they are low on the food chain, they accumulate significantly less mercury than larger, predatory fish, making them a safer option for frequent consumption, even for pregnant women.

Sardines are an incredible source of omega-3s, and when canned with bones, they provide a robust amount of calcium and phosphorus for bone health, which is especially beneficial for those with dairy allergies or lactose intolerance. They are also rich in Vitamin B12, selenium, and protein, and have antioxidant properties. Their affordability and long shelf life in canned form make them an accessible and convenient superfood for many.

The Case for Mackerel

Another excellent fatty fish is mackerel, particularly smaller varieties like Atlantic mackerel. Like salmon and sardines, it is high in omega-3 fatty acids, protein, and selenium. Mackerel is a phenomenal source of Vitamin B12, with a 100-gram serving providing well over the recommended daily allowance for adults.

It is important to differentiate between species when choosing mackerel. Atlantic or Pacific chub mackerel are considered a “best choice” due to lower mercury content, while King mackerel is on the "avoid" list for its high mercury levels. Always check the source and species to ensure a healthy choice. For those seeking diversity in their fish intake, mackerel offers a rich, oily flavor and a different nutritional profile than salmon or sardines.

The Role of Mercury in Fish

Mercury is a naturally occurring element that is more concentrated in larger, predatory fish higher up the food chain. This can be particularly harmful to developing fetuses and young children, making low-mercury fish a top priority for certain populations. While the health benefits of eating fish generally outweigh the risks for most people, choosing lower-mercury options is a safe and simple strategy for everyone. Large fish to avoid or limit due to high mercury levels include swordfish, king mackerel, marlin, and some types of tuna. Opting for smaller, oily fish like sardines and salmon, both recommended for their low mercury content, provides excellent nutrition with minimal risk.

How to Pick the Healthiest Fish

When navigating the seafood aisle, consider a balance of nutritional content, mercury levels, and sustainability. Certified sustainable fish, often indicated by labels from organizations like the Marine Stewardship Council (MSC), ensures you are making an environmentally responsible choice that supports ocean health.

Comparison Table: Salmon vs. Sardines vs. Mackerel


Feature	Wild Salmon	Canned Sardines	Atlantic Mackerel
Primary Nutrient	Omega-3s (EPA/DHA), Vitamin B12, D, Selenium	Omega-3s (EPA/DHA), Calcium, Vitamin D, B12	Omega-3s (EPA/DHA), Vitamin B12, Selenium, Protein
Mercury Levels	Low	Very Low	Low (Atlantic)
Sustainability	Wild Alaskan is typically sustainable, check for certifications	Generally very sustainable due to low food chain position	Varied, Atlantic mackerel is a good choice
Cost	Typically higher	Very affordable	Moderate
Convenience	Versatile, fresh or frozen fillets	Highly convenient, shelf-stable, no prep needed	Available fresh, smoked, or canned

Conclusion: The Healthiest Fish is a Smart Choice

While there is no single "number one healthy fish in the world," wild-caught salmon and sardines are arguably the top contenders due to their outstanding nutritional profiles, low mercury content, and heart-healthy benefits. Mackerel also offers a fantastic nutritional punch, particularly smaller species. Ultimately, the healthiest choice is an informed one that considers a balance of omega-3s, minimal mercury, and sustainable sourcing. By rotating a variety of these nutrient-dense fish into your diet, you can maximize health benefits while minimizing environmental impact. For more information on seafood recommendations and sustainability, the Monterey Bay Aquarium's Seafood Watch is an excellent resource, offering regional guides to help consumers make responsible choices. https://www.seafoodwatch.org/

Frequently Asked Questions

While salmon is famous for its omega-3 content, smaller fish like sardines and mackerel also contain very high levels of these essential fatty acids per serving.

Both farmed and wild salmon are healthy choices. Wild salmon is slightly higher in certain nutrients and lower in fat and calories, while sustainably farmed salmon is also an excellent source of omega-3s.

Large predatory fish, such as swordfish, king mackerel, marlin, and tilefish from the Gulf of Mexico, should be avoided or limited due to their high mercury content.

Yes, canned sardines are often considered more nutritious than fresh, especially because the bones are soft and edible, providing a significant boost of calcium.

Getting omega-3s from whole fish is more effective than supplements, as it provides a broader range of nutrients and the fats are more easily absorbed. Plus, you get protein and other vitamins.

Small, fast-growing fish like sardines, anchovies, and Atlantic mackerel are often considered highly sustainable due to their low position on the marine food chain and quick reproductive cycles.

The American Heart Association recommends eating at least two servings of non-fried fish per week, with a focus on fatty fish like salmon, sardines, and mackerel.