What is the healthiest fish you can eat in the world?

November 2, 2025 •

3 min read

According to the American Heart Association, eating at least two servings of fish per week can significantly lower your risk of heart attack and stroke. To make the best choice, it's essential to understand what is the healthiest fish you can eat in the world, prioritizing those that are rich in essential nutrients, low in contaminants like mercury, and sustainably sourced.

Quick Summary

The healthiest fish are those high in omega-3 fatty acids, low in mercury, and come from sustainable sources. Top choices include sardines, wild-caught salmon, and Atlantic mackerel. Factors like mercury levels and sustainability certifications are key to making informed decisions about seafood consumption.

Key Points

Sardines are a top contender: Small, inexpensive, and packed with omega-3s, calcium, and vitamin D, with very low mercury levels.
Wild-caught salmon is highly nutritious: A rich source of omega-3s, protein, and vitamins D and B12, with a clean nutritional profile.
Opt for smaller, oily fish: Species like sardines, mackerel, and herring are lower on the food chain, meaning they have lower mercury concentrations.
Prioritize low-mercury fish: Limit or avoid large predatory fish such as shark, swordfish, and king mackerel, which have the highest levels of mercury.
Look for sustainability certifications: Choose seafood with eco-labels like the Marine Stewardship Council (MSC) or use guides like Monterey Bay Aquarium's Seafood Watch.
Canned fish can be a healthy, affordable option: Canned sardines and light tuna (skipjack) are convenient sources of omega-3s and other nutrients.

What Defines the Healthiest Fish?

Determining the healthiest fish involves considering a trifecta of factors: high nutritional value, low mercury content, and environmental sustainability. Small, oily fish often excel in these areas, as their shorter lifespans and position lower on the food chain mean they accumulate fewer contaminants while packing in powerful doses of omega-3s. Sustainability is also paramount, ensuring that fishing practices don't harm marine ecosystems and that fish populations can continue to thrive.

The Contenders for the Healthiest Fish

Here are some of the top contenders, consistently recommended by health and environmental organizations:

Sardines: These small, inexpensive fish are nutrient powerhouses, loaded with omega-3 fatty acids, calcium (when eaten with the bones), and vitamin D. Since they are small and reproduce quickly, they are typically low in mercury and considered a sustainable choice. Canned sardines are a convenient and affordable option.
Wild-Caught Salmon: Often hailed as one of the best sources of omega-3s, wild-caught salmon also offers high-quality protein, vitamin B12, and vitamin D. Wild Alaskan salmon, in particular, is known for its purity and sustainability. The natural diet of wild salmon results in a more vibrant color and different nutritional profile than farmed varieties.
Mackerel: Atlantic mackerel is a smaller, oily fish rich in omega-3s and selenium. It is a good source of B vitamins and is generally a more sustainable choice than larger, high-mercury king mackerel.
Herring: Similar to sardines, herring is a small, oily fish that is an excellent source of omega-3s, vitamin D, and B12. It typically has low contaminant levels, making it a safe and nutritious option.
Rainbow Trout: Often farmed in freshwater ponds with strong sustainability practices, rainbow trout is rich in omega-3 fatty acids and vitamin D. It provides a milder, less pungent flavor than salmon, making it a great entry point for those new to seafood.

Comparing the Healthiest Fish: Omega-3 and Mercury Levels

To help you decide, here is a comparison of some of the healthiest fish based on key factors:


Feature	Sardines	Wild-Caught Salmon	Atlantic Mackerel	Canned Light Tuna	Cod
Omega-3s (High/Medium)	High	High	High	Medium	Low
Mercury Levels (Low/Med/High)	Low	Low	Low	Low	Low
Key Nutrients	Calcium, Vitamin D, Selenium	Protein, Vitamin D, B12, Selenium	Protein, Selenium, B Vitamins	Protein, Selenium, B12	Protein, B12
Sustainability	High	High (specifically Alaskan)	Moderate to High	Varies by method	High

Risks of High-Mercury Fish and Why Smaller is Often Better

Larger, predatory fish like swordfish, shark, king mackerel, and some tuna species are higher in the aquatic food chain and accumulate more methylmercury. High exposure to methylmercury can have negative neurological and behavioral effects, and poses particular risks for pregnant women, breastfeeding mothers, and young children. Smaller, oily fish like sardines and anchovies, on the other hand, have significantly lower mercury levels because they have shorter lifespans and eat lower on the food chain, making them a safer choice for frequent consumption.

The Importance of Sustainability

Choosing sustainable seafood is crucial for both personal health and the planet. Practices like overfishing, habitat destruction, and excessive bycatch threaten marine ecosystems. When you select sustainably sourced seafood, you support fisheries that adhere to responsible management practices, ensuring healthy fish stocks for future generations. Look for certifications from reputable organizations like the Marine Stewardship Council (MSC) or use the Monterey Bay Aquarium's Seafood Watch guide to make environmentally conscious choices.

The Final Verdict on Healthiest Fish

While a variety of fish offer unique health benefits, sardines and wild-caught salmon stand out as arguably the healthiest fish you can eat. Sardines offer an unparalleled combination of omega-3s, calcium, and vitamin D, all for a low cost and with minimal mercury. Wild-caught salmon provides similar fatty acids along with other essential vitamins and minerals, and when sourced responsibly, offers a clean, nutritious profile. Mackerel and herring are also fantastic options. By rotating these smaller, low-mercury, high-omega-3 fish into your diet, you can maximize your nutritional intake while minimizing health risks.

Frequently Asked Questions

Among commonly available options, sardines and Atlantic mackerel are often cited for their very high omega-3 fatty acid content. Wild-caught salmon is also an excellent source.

Fish with high mercury levels that should be avoided or limited, especially by pregnant women and children, include shark, swordfish, king mackerel, and bigeye tuna.

It depends. Wild-caught fish often have lower contaminant levels, while sustainably farmed fish can have consistent omega-3 levels and may be monitored for quality. Smaller, wild-caught fish lower on the food chain generally have the lowest risk of contamination.

Yes, canned sardines are very healthy. When you eat them with the bones, they are an excellent source of calcium, in addition to being rich in omega-3s and vitamin D. Look for options canned in olive oil or water.

The American Heart Association recommends eating two servings of fish per week, particularly fatty fish. For low-mercury options, you can safely eat them more frequently.

Smaller, fast-reproducing fish lower on the food chain, such as sardines and mussels, are often the most sustainable choice. Looking for certification from the Marine Stewardship Council (MSC) is also a good practice.

Tuna can be healthy, but it's important to be mindful of mercury levels. Canned light tuna (typically skipjack) is a better, lower-mercury choice than albacore or large yellowfin and bigeye tuna. Tuna is a good source of protein and selenium, but not considered an oily fish like salmon or sardines.