Which white fish has the lowest mercury?

October 19, 2025 •

4 min read

According to the FDA, many popular white fish varieties are excellent choices for a low-mercury diet. Choosing fish with low mercury levels is important for everyone, but particularly for pregnant women, nursing mothers, and young children, whose developing nervous systems are most sensitive to the effects of methylmercury.

Quick Summary

A comprehensive guide to identifying white fish varieties with the lowest mercury content, including pollock, tilapia, and cod. Includes information on mercury accumulation, health benefits, and safe consumption recommendations for informed seafood choices.

Key Points

Low Mercury Choices: Alaska Pollock, Tilapia, Cod, and Haddock are among the safest white fish with the lowest mercury concentrations.
Bioaccumulation Explained: Mercury levels in fish increase with their size and position on the food chain; smaller, shorter-lived fish like pollock accumulate less.
Guidelines for Sensitive Groups: Pregnant women, nursing mothers, and young children should prioritize low-mercury fish from the 'Best Choices' list, consuming 8–12 ounces per week.
Nutritional Benefits: Low-mercury white fish provides lean protein, selenium, B vitamins, and omega-3 fatty acids, supporting heart and brain health.
Responsible Sourcing: Choosing wild-caught or sustainably certified fish, such as MSC-certified Alaska pollock, can help ensure both low mercury levels and environmental protection.
High-Mercury Fish to Avoid: Larger predatory fish like swordfish and king mackerel should be limited or avoided due to their higher mercury content.

Understanding Mercury in Seafood

Mercury is a naturally occurring heavy metal that finds its way into waterways and oceans through industrial pollution and natural processes. Once in the water, microorganisms convert it into methylmercury, which is then absorbed by aquatic life. The concentration of mercury in fish increases as it moves up the food chain, a process known as bioaccumulation. This means that large, long-lived predatory fish, such as swordfish and king mackerel, tend to have the highest mercury levels, while smaller, shorter-lived species generally contain less.

For consumers, this understanding is key to making safe seafood choices. The United States Environmental Protection Agency (EPA) and Food and Drug Administration (FDA) provide guidance on which fish are considered 'Best Choices' with very low mercury levels, making them safe for frequent consumption. These guidelines are particularly important for sensitive populations, but they are useful for anyone looking to reduce their mercury exposure while still enjoying the significant nutritional benefits of fish.

The Top Low-Mercury White Fish Choices

When seeking out low-mercury white fish, several species consistently appear on recommended lists from health organizations. These fish are typically found lower on the food chain, meaning they consume smaller organisms with minimal mercury accumulation.

Alaska Pollock

Wild Alaska Pollock is a standout for several reasons. It has a mild flavor and flaky texture, making it a versatile and popular choice for everything from fish sticks to fillets. Nutritionally, it is an excellent source of lean protein, selenium, and B vitamins, and provides a significant dose of omega-3 fatty acids with very low mercury levels. Most Alaska pollock is wild-caught and certified sustainable, adding to its appeal as a responsible and healthy option.

Tilapia

Often a staple in aquaculture, tilapia is another white fish with an exceptionally low mercury count. It has a very mild taste, which makes it a good option for those new to eating fish. Because much of the tilapia consumed is farm-raised, it is important to choose responsibly farmed products to ensure quality. It offers a low-fat protein source and is also rich in vitamin B12.

Cod

Cod is a beloved, flaky white fish available in several varieties, including Pacific and Atlantic. It is considered a low-mercury fish and is a rich source of lean protein, iodine, selenium, and B vitamins. This makes it a highly nutritious choice for a balanced diet. Its mild flavor profile makes it suitable for a wide range of recipes, from baking and grilling to traditional fish and chips.

Haddock

Haddock, a close relative of cod, also boasts low mercury levels and a delicate, slightly sweet flavor. It is an excellent source of high-quality protein and is low in fat. Like cod, it provides a good amount of selenium, which is crucial for thyroid function, and B vitamins that support energy production. Its flaky texture makes it a great choice for steaming, baking, or pan-frying.

Flounder and Sole

Both flounder and sole are flatfish known for their delicate flavor and very low mercury content. They provide a good source of lean protein and vitamin B12. Their thin fillets cook quickly and are perfect for light, healthy meals. These fish are bottom-dwellers, which contributes to their lower mercury levels.

Comparative Table: Mercury Levels in Popular White Fish

To help you compare, here's a table summarizing the mercury content in parts per million (ppm) based on data compiled from FDA testing.


White Fish Species	Mercury Concentration (Mean PPM)	Relative Mercury Level	Notes
Scallop	0.003	Very Low	Shellfish, but excellent low-mercury option
Tilapia	0.013	Very Low	Farm-raised is a consistent low-mercury choice
Catfish	0.024	Very Low	Farm-raised tends to have even lower levels
Pollock	0.031	Very Low	A wild-caught, sustainable, low-mercury option
Haddock	0.055	Low	A popular, mild-flavored choice
Flounder / Sole	0.056	Low	Both are flatfish with similar low-mercury content
Cod	0.111	Moderate-Low	A very popular choice, but still higher than some
Halibut	0.241	Moderate	Higher mercury content, should be consumed in moderation

Safe Consumption and Guidelines

For most healthy adults, consuming a variety of fish is safe and beneficial, and the risk of mercury accumulation is minimal with moderate intake. However, those in sensitive groups—pregnant or breastfeeding women, young children—should be more cautious and prioritize fish from the 'Best Choices' list. The FDA and EPA advise these groups to eat 8–12 ounces of low-mercury fish per week to reap the benefits of omega-3s and protein while minimizing mercury exposure.

One simple rule of thumb for all consumers is to consider the size and lifespan of the fish. Smaller, shorter-lived fish like tilapia, pollock, and flounder will almost always contain less mercury than larger, longer-lived predators like swordfish. You can also explore options certified by organizations such as the Marine Stewardship Council (MSC) for both sustainability and safety assurance.

Incorporating Low-Mercury White Fish into Your Diet

Making healthy choices with low-mercury fish can be delicious and easy. Baking or grilling fillets with herbs and lemon is a simple way to prepare cod, haddock, or flounder. Tilapia can be used for light and flavorful fish tacos. Pollock is an excellent, budget-friendly option for homemade fish cakes or fish sandwiches. By varying the types of fish you eat, you can enjoy a wide range of flavors and nutrients without over-relying on any single source. For more cooking inspiration and information on sustainable seafood practices, the Monterey Bay Aquarium's Seafood Watch is a great resource.

Conclusion

While almost all fish contain some level of mercury, certain white fish varieties stand out for their low-risk profiles. Pollock, tilapia, cod, haddock, flounder, and sole are all excellent, nutrient-rich options for those seeking to minimize their mercury intake. By choosing fish lower on the food chain, you can safely enjoy seafood as a vital part of a healthy diet. Always follow the latest guidelines from health authorities, especially if you belong to a sensitive population group, to ensure you are making the best and safest choices for yourself and your family.

Frequently Asked Questions

Pregnant women should prioritize white fish from the FDA's 'Best Choices' list, which includes Alaska pollock, tilapia, and cod, due to their very low mercury levels. Following the recommended consumption of 8–12 ounces per week is a safe approach.

No, cod is not considered a high-mercury fish. While it contains some mercury, its levels are significantly lower than large predators, making it a safe choice for regular consumption in moderation.

Bioaccumulation is the process by which mercury concentrations increase in fish as they move up the food chain. Smaller fish eat contaminated plankton, and larger predatory fish then consume those smaller fish, causing the mercury to accumulate in their systems over time.

This depends on the species and the quality of the farming process. However, some farm-raised fish, like tilapia, are known to be low in mercury because their controlled diet contains fewer contaminants than their wild counterparts.

Eating low-mercury white fish provides lean, high-quality protein, essential vitamins (like B12 and D), and minerals such as selenium. Some, like pollock, also offer heart-healthy omega-3 fatty acids.

For most people, it is safe to eat a variety of low-mercury fish several times a week. The FDA recommends that sensitive populations consume 8–12 ounces per week from the 'Best Choices' list.

No. Canned light tuna (typically skipjack) has significantly lower mercury levels and is a 'Best Choice'. Canned albacore ('white') tuna has higher mercury levels and should be consumed less frequently.