What are the lowest mercury fish to eat?

January 3, 2026 •

4 min read

According to the World Health Organization, mercury can have toxic effects on the nervous, digestive, and immune systems. However, eating fish is an important source of omega-3 fatty acids and protein, so it is vital to know what are the lowest mercury fish to eat to minimize risks. This guide will help you make informed decisions when selecting seafood.

Quick Summary

This article provides a detailed list of fish with the lowest mercury content, helping consumers, including pregnant women and children, make safer and healthier seafood choices. It explains why some fish have higher mercury levels and offers a comparison table, a seafood selection strategy, and frequently asked questions about mercury in fish.

Key Points

Small fish, less mercury: Smaller, younger fish and those lower on the food chain, like sardines, tend to have the lowest mercury concentrations.
Predatory fish, more mercury: Larger, predatory fish like shark, swordfish, and king mackerel accumulate the highest levels of mercury and should be limited or avoided.
Safe options for all: Seafood such as salmon, shrimp, tilapia, and canned light tuna are considered 'Best Choices' for low mercury content.
Canned tuna caution: While canned light tuna is low in mercury, canned albacore (white) tuna has a moderate level and should be consumed less frequently.
Vulnerable groups need care: Pregnant women, breastfeeding mothers, and young children should strictly adhere to guidelines for low-mercury fish intake.
Check local advisories: For fish caught from local waters, always check for specific local advisories on mercury levels and other contaminants.
Benefit outweighs risk (with caution): For most healthy adults, the nutritional benefits of eating low-mercury fish outweigh the risks, as long as high-mercury species are limited.
Farmed vs. wild: Some studies suggest that farmed fish may have slightly lower mercury levels than wild-caught fish, though this can vary by species.

Understanding Mercury in Fish and Its Risks

Mercury is a naturally occurring element that is released into the environment through industrial pollution and natural processes. In aquatic environments, microbes convert it into methylmercury, which is highly toxic and accumulates in the fatty tissues of fish. This process is known as bioaccumulation and biomagnification, meaning that mercury concentrations increase as you move up the food chain. Therefore, larger, older, and predatory fish tend to have the highest levels of mercury. Exposure to high levels of mercury can have serious health consequences, particularly for vulnerable populations like pregnant women, breastfeeding mothers, and young children, as it can affect the nervous system and brain development. Making informed choices about which fish to eat is crucial for reaping the nutritional benefits of seafood while minimizing the health risks associated with mercury.

The Lowest Mercury Fish: Best Choices

For those looking to enjoy seafood with minimal mercury exposure, selecting fish that are smaller, have shorter lifespans, and are lower on the food chain is the best strategy. The following list, based on guidelines from the FDA and other health organizations, details some of the safest options.

Anchovies: These small, oily fish have very low mercury levels and are an excellent source of omega-3s.
Sardines: Like anchovies, sardines are small, low-mercury, and rich in omega-3 fatty acids and calcium.
Salmon: Both wild-caught Alaskan and farmed salmon are generally low in mercury and packed with heart-healthy omega-3s.
Tilapia: Commonly farm-raised, tilapia has very low mercury levels.
Pollock: A flaky white fish, pollock is a sustainable option with one of the lowest mercury concentrations.
Catfish: Farm-raised catfish is a consistently low-mercury choice.
Shrimp: These are a shellfish option with exceptionally low mercury content.
Squid (Calamari): Despite being a cephalopod, squid contains very low mercury levels.
Scallops: Another shellfish with remarkably low mercury levels.
Clams and Oysters: These are also excellent, low-mercury shellfish choices.
Cod: Known for its mild flavor and low fat content, cod is a great low-mercury option.
Haddock: Similar to cod, haddock is a white fish with low mercury levels.
Trout (Freshwater): This species is consistently low in mercury.
Mackerel (Atlantic): It is important to distinguish Atlantic mackerel, which is low in mercury, from King mackerel, which is high.

Making Safer Choices for At-Risk Groups

For pregnant and breastfeeding women, and young children, it is especially important to prioritize low-mercury options to support healthy development. Health organizations recommend that these groups consume 8 to 12 ounces of seafood from the 'Best Choices' list per week. When consuming canned tuna, they should opt for 'canned light' tuna (usually skipjack) over canned 'white' (albacore), which has higher mercury levels. The FDA provides detailed guidelines to help these populations make the safest choices.

Mercury Levels in Popular Seafood: A Comparison

To help you visualize the differences in mercury content, the following table compares common seafood options, categorized as 'Best,' 'Good,' and 'Avoid' choices based on typical mercury concentrations.


Seafood Type	Mercury Level (ppm)	Recommended Consumption (for adults)
Best Choices (2-3 servings/week)	Low
Shrimp	< 0.01	2-3 servings per week
Sardines	0.013	2-3 servings per week
Salmon	0.022	2-3 servings per week
Tilapia	0.01	2-3 servings per week
Pollock	0.031	2-3 servings per week
Canned Light Tuna	0.13	2-3 servings per week
Good Choices (1 serving/week)	Medium
Tuna (Albacore/White)	0.35	1 serving per week
Halibut	0.24	1 serving per week
Mahi Mahi	0.18	1 serving per week
Choices to Avoid (Highest Mercury)	High
Shark	0.98	Avoid
Swordfish	1.0	Avoid
King Mackerel	0.73	Avoid
Bigeye Tuna	0.69	Avoid

What Factors Influence Mercury Levels?

Several factors contribute to the amount of mercury found in different fish species.

Fish Age and Size

Larger, older fish have had more time to accumulate mercury in their bodies. As they consume smaller fish, the concentration of mercury increases, a process called biomagnification. This is why top predators like shark and swordfish have the highest mercury levels.

Diet and Trophic Level

Fish that feed on algae or smaller organisms generally have lower mercury levels than predatory fish. For example, anchovies and sardines, which feed lower on the food chain, have some of the lowest mercury concentrations.

Water Source

Mercury levels can also vary depending on the environment. Fish caught in more polluted waters may contain higher levels of mercury or other contaminants. This is why local fish advisories from sources like the EPA are important to consult, especially for freshwater fish.

Conclusion: Making Informed Seafood Choices

Eating fish offers significant health benefits, and by choosing species with low mercury content, you can safely enjoy a nutritious diet. The best strategy is to focus on smaller, non-predatory fish and shellfish such as salmon, sardines, shrimp, and tilapia. For vulnerable populations, such as pregnant women and young children, paying close attention to recommended serving sizes and selecting low-mercury options is even more critical. By following expert guidelines and using resources like the FDA's consumption advice, you can confidently navigate your seafood choices and maximize the health rewards of a fish-rich diet.

For more detailed information on specific fish species and mercury levels, consult the FDA's technical guidance on eating fish and shellfish: https://www.fda.gov/food/environmental-contaminants-food/technical-information-development-fdaepa-advice-about-eating-fish-those-who-might-become-or-are.

Frequently Asked Questions

Methylmercury is an organic form of mercury that is highly toxic to humans and is the form found in fish. It is a potent neurotoxin that can cause damage to the nervous system, kidneys, and liver, especially in developing fetuses and young children.

Larger, predatory fish are higher up on the food chain and engage in a process called biomagnification. As they eat smaller fish that have already accumulated some mercury, the mercury concentrations build up in their fatty tissues over their longer lifespans.

Yes, but they should choose low-mercury fish from the 'Best Choices' list and follow recommended weekly serving limits from health authorities like the FDA. The omega-3s in fish are important for brain development, making informed consumption crucial.

This depends on the type of canned tuna. Canned 'light' (skipjack) tuna is low in mercury and can be consumed regularly. Canned 'white' (albacore) tuna is higher in mercury, and intake should be limited, especially for pregnant women and children.

No, cooking fish does not reduce its mercury content. Mercury is bound to the fish's muscle tissue and is not eliminated through heat, though cooking does remove other contaminants.

In some cases, yes. Farmed fish may contain less mercury because their diet is controlled and they have less exposure to polluted waterways than wild fish. However, the difference can be small and varies by species.

Authoritative sources include the U.S. Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA), which provide detailed, species-specific advice and monitoring data. Consulting reputable environmental non-profits can also be helpful.