What White Fish Is Lowest in Mercury? A Complete Seafood Guide

October 30, 2025 •

3 min read

Did you know that mercury levels in fish are higher in larger, older predatory species due to a process called bioaccumulation? Knowing what white fish is lowest in mercury is crucial for making healthy dietary choices, especially for vulnerable populations like pregnant women and young children.

Quick Summary

This article provides an in-depth guide to low-mercury white fish, outlining species like cod, pollock, and tilapia, along with key safety tips and FDA recommendations for a balanced and nutritious diet.

Key Points

Pollock and Catfish are Top Choices: Farmed catfish and wild Alaska pollock consistently rank among the white fish with the lowest mercury levels, making them safe for regular consumption.
Size and Diet Matter: Mercury bioaccumulates, meaning smaller, shorter-lived fish lower on the food chain contain less mercury than larger, predatory species.
Cooking Doesn't Remove Mercury: Since methylmercury is stored in muscle tissue, cooking fish will not reduce its mercury content.
Prioritize Farmed Over Wild: For species like catfish, farmed options often contain lower mercury levels than their wild-caught counterparts.
Vulnerable Groups Need Caution: Pregnant women, breastfeeding mothers, and young children should strictly follow FDA recommendations, sticking to 'Best Choices' fish to minimize exposure.
Diversify Your Choices: To ensure a wide range of nutrients and prevent overconsumption of any single contaminant, vary the types of fish and seafood you eat weekly.

For many health-conscious individuals, seafood is a vital part of a nutritious diet, providing essential protein and omega-3 fatty acids. However, concerns over mercury contamination often arise. The good news is that by making informed choices, you can safely enjoy the benefits of fish. This comprehensive guide breaks down what white fish is lowest in mercury, offers a practical comparison, and provides advice on minimizing risk while maximizing nutritional intake.

The Science Behind Mercury in Fish

Methylmercury, the primary form of mercury found in fish, is a neurotoxin that can be harmful in high concentrations, particularly to the developing brains of fetuses and young children. It enters the aquatic food chain and builds up in organisms through a process known as bioaccumulation. Larger, older predatory fish, such as sharks, swordfish, and king mackerel, are at the top of this food chain and therefore accumulate the highest levels of mercury.

Top Low-Mercury White Fish Options

Fortunately, many delicious and nutritious white fish options have very low mercury levels, making them excellent choices for frequent consumption. The FDA and EPA classify several species as 'Best Choices' for low mercury. These include:

Cod: A flaky, mild-flavored fish known for its high protein and low-fat content. Atlantic cod has relatively low mercury levels.
Pollock: Often used in fish sticks and fast-food sandwiches, Alaska pollock is a sustainable and low-mercury option.
Tilapia: This farmed freshwater fish is known for its low mercury content, though wild-caught can sometimes have higher toxin levels depending on the source. It's a great source of lean protein.
Haddock: Similar to cod but with a slightly sweeter taste, haddock is another low-mercury white fish.
Catfish (Farm-raised): Farm-raised catfish is a reliable low-mercury choice, unlike some wild-caught varieties.
Sole and Flounder: These bottom-dwelling fish generally have very low mercury concentrations.
Hake: A deep-sea fish that is popular in European cuisine and low in mercury.

Comparing Mercury Levels: A Quick Guide

To help visualize the difference, here is a comparison of mercury levels in parts per million (ppm) for several common seafood choices based on FDA data:


Fish Type	Average Mercury (ppm)	Recommendation
Scallops	0.003	Best Choice (Lowest)
Pollock	0.031	Best Choice
Haddock	0.055	Best Choice
Cod	0.111	Best Choice
Tilapia	Low to Moderate	Best Choice (especially farmed)
Canned Light Tuna	0.128	Best Choice
Yellowfin Tuna	0.270	Good Choice (Moderate)
Swordfish	0.995	Avoid (Highest)

Making Safe Choices and Preparations

Beyond choosing the right type of fish, smart purchasing and preparation habits are key to minimizing your mercury exposure:

Diversify Your Diet: Don't rely on just one type of seafood. Mixing up your fish and shellfish choices ensures you get a broader range of nutrients and reduces the risk of mercury accumulation from a single source.
Prioritize Farmed Fish: Research indicates that some farmed fish, like catfish and salmon, often have lower mercury concentrations than their wild-caught counterparts.
Choose Smaller Fish: As a general rule, smaller, younger fish that are lower on the food chain will have less accumulated mercury.
Cooking Methods Don't Remove Mercury: It's a common misconception that cooking methods can remove mercury. Since mercury is stored in the muscle tissue, trimming fat or broiling will not reduce the mercury content. Always cook to a safe internal temperature to kill bacteria, but don't expect it to eliminate mercury.
Stay Informed: For fish caught recreationally, check with local health departments for advisories about mercury levels in your specific area.

Special Dietary Considerations

Certain groups are more vulnerable to the effects of methylmercury and should follow stricter guidelines. This includes pregnant or breastfeeding women, and young children. The FDA and EPA advise these groups to eat 2-3 servings (8-12 ounces) per week of low-mercury fish from their 'Best Choices' list, and limit consumption of 'Good Choices' fish. For example, canned light tuna is a 'Best Choice,' but albacore (white) tuna is higher in mercury and should be limited to 6 ounces per week.

Conclusion: The Path to Healthier Seafood Consumption

The benefits of consuming fish, including essential nutrients for heart and brain health, far outweigh the potential risks of mercury exposure for most people. By understanding what white fish is lowest in mercury, you can confidently include seafood in your diet. Opt for species like pollock, haddock, and farm-raised catfish, diversify your selections, and stay within recommended consumption guidelines. These practices allow you to enjoy the delicious taste and significant health benefits of seafood without concern. The key is balance, variety, and making informed choices. You can find more detailed advice on the FDA Advice on Eating Fish page.

Frequently Asked Questions

Among white fish and seafood, scallops, shrimp, and anchovies tend to have the absolute lowest mercury levels. Pollock and haddock are also very low, while cod has slightly more but is still considered a 'Best Choice' by the FDA.

Some studies suggest that farmed fish, particularly species like salmon and catfish, can have lower mercury levels than their wild-caught counterparts. This is often due to controlled diets and shorter life cycles in aquaculture environments.

It's best to check local advisories from your state or local health department regarding fish caught in your area. Mercury levels can vary widely based on specific water pollution, so always research your local waters before consuming.

Canned 'light' tuna, which is typically made from skipjack, has significantly lower mercury than canned 'white' or albacore tuna. The FDA recommends limiting albacore to 6 ounces per week while allowing more light tuna.

For the general population, eating two to three servings of low-mercury fish per week is recommended. Vulnerable groups like pregnant women are advised to eat 8-12 ounces per week from the 'Best Choices' list.

Yes, larger and older fish tend to have higher levels of mercury due to a process called bioaccumulation, where mercury builds up in their systems over their lifetime.

The FDA and EPA classify fish based on their mercury levels. 'Best Choices' have the lowest levels and can be eaten more frequently, while 'Choices to Avoid,' such as swordfish and shark, have the highest levels and should be avoided, especially by vulnerable populations.