How much fish to eat to avoid mercury poisoning?

November 15, 2025 •

3 min read

According to the U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA), eating at least 8 ounces of seafood per week is part of a healthy dietary pattern. This guide will explain how much fish to eat to avoid mercury poisoning while still enjoying the nutritional benefits of seafood.

Quick Summary

This guide provides clear, science-backed recommendations for safe fish consumption to minimize mercury exposure. It details which fish have the highest and lowest mercury levels and offers tailored advice for adults, pregnant women, and children to help balance the health benefits of seafood with safety concerns.

Key Points

Variety is Key: Eating a diverse range of seafood, especially low-mercury options, helps minimize overall mercury exposure.
Follow FDA/EPA Guidelines: Adhere to the recommended 2-3 servings (8-12 oz) per week for most adults, prioritizing 'Best Choices' fish.
Consider High-Risk Groups: Pregnant women, breastfeeding mothers, and young children have stricter limits and must avoid the highest-mercury fish.
Be Mindful of Tuna: Canned light tuna is a 'Best Choice' for regular consumption, while canned albacore (white) tuna should be limited to one serving per week due to higher mercury levels.
Avoid High-Mercury Fish: Stay away from species like shark, swordfish, and king mackerel, which accumulate the highest concentrations of mercury.
Check Local Advisories: When eating recreationally caught fish, consult local health advisories for specific guidance based on regional water contamination.

Understanding Mercury in Fish

Mercury is a naturally occurring element that is released into the environment through human activities like coal-burning and volcanic eruptions. In water, it transforms into methylmercury, a highly toxic organic compound that accumulates in fish tissue. The concentration of mercury varies greatly among different fish species. Larger, longer-living predatory fish, such as shark and swordfish, tend to have the highest concentrations because they consume smaller fish, leading to a process called bioaccumulation. Smaller fish and shellfish typically contain much lower levels of mercury, making them safer choices for regular consumption.

The Importance of Variety

To reap the nutritional rewards of fish, such as heart-healthy omega-3 fatty acids, protein, and essential vitamins, without over-exposing yourself to mercury, the key is variety. The FDA and EPA categorize fish into 'Best Choices,' 'Good Choices,' and 'Choices to Avoid' based on their mercury content, making it easier to make informed decisions. By focusing on a diverse range of seafood from the 'Best Choices' list, you can enjoy the health benefits while keeping mercury intake low.

Official Guidelines for Fish Consumption

For the general adult population: The FDA and EPA recommend eating 2 to 3 servings (8 to 12 ounces) of fish per week from the 'Best Choices' category. A typical serving size for an adult is 4 ounces, which is about the size of a human palm.

For pregnant and breastfeeding women: This group is particularly sensitive to mercury because it can affect a baby's developing nervous system. The recommendation is 2 to 3 servings (8 to 12 ounces) per week of low-mercury 'Best Choices' fish. It is crucial for them to completely avoid the 'Choices to Avoid' list.

For children: Fish provides important nutrients for a child's growth and development. Children should have 2 servings of fish per week from the 'Best Choices' category, with smaller portion sizes appropriate for their age. A suggested portion is 1 ounce for ages 1-3, 2 ounces for ages 4-7, and 3-4 ounces for older children.

Lowering Mercury Exposure While Eating Fish

Choose Wisely: Prioritize fish from the 'Best Choices' list, which includes salmon, tilapia, cod, sardines, and canned light tuna.
Limit Higher-Mercury Fish: If you do eat fish from the 'Good Choices' category, such as albacore tuna, limit consumption to one serving per week.
Check Local Advisories: For fish caught in local waters, check with state and local health departments for specific advisories, as some areas may have higher mercury levels.
Vary Your Seafood: Don't rely on just one type of fish. Diversifying your seafood choices from the 'Best Choices' category helps to further minimize exposure.

Comparison Table: Mercury Levels in Common Seafood


Seafood Type	Mercury Level Category	Safe Weekly Servings (Adult)
Salmon	Best Choice (Low)	2–3 servings (8-12 oz)
Shrimp	Best Choice (Low)	2–3 servings (8-12 oz)
Canned Light Tuna	Best Choice (Low)	2–3 servings (8-12 oz)
Cod	Best Choice (Low)	2–3 servings (8-12 oz)
Albacore Tuna	Good Choice (Moderate)	1 serving (4 oz)
Swordfish	Choices to Avoid (Highest)	0 servings for high-risk groups; limited for others
Shark	Choices to Avoid (Highest)	0 servings for high-risk groups; limited for others

Conclusion

Making informed choices about the type and amount of fish you eat is the most effective way to prevent mercury poisoning. By following the recommendations from authoritative bodies like the FDA and EPA, you can confidently include fish in a healthy diet and benefit from its nutritional value without undue risk. The key is to prioritize a variety of low-mercury options, limit fish with higher mercury content, and pay special attention to consumption guidelines for sensitive populations like pregnant women and children. A balanced approach ensures you can enjoy the many benefits of seafood for years to come.

For more detailed information and the complete list of fish categories, you can consult the official FDA guidelines.

Frequently Asked Questions

Fish absorb methylmercury from the environment, primarily through the water they live in and the smaller fish they eat. Larger predatory fish higher up the food chain accumulate more mercury over their lifespan through this process of bioaccumulation.

Some of the best 'Best Choices' for low-mercury fish include salmon, sardines, tilapia, shrimp, scallops, cod, and canned light tuna. These are generally smaller, shorter-lived fish.

Fish with the highest mercury levels that should be avoided or severely limited include shark, swordfish, king mackerel, orange roughy, and bigeye tuna.

The type of tuna matters. You can safely eat 2 to 3 servings of canned light tuna per week. However, due to its higher mercury content, canned albacore (white) tuna should be limited to one serving per week for adults.

No, mercury is integrated into the muscle tissue of the fish and cannot be removed by cooking, cleaning, or trimming. The best way to reduce exposure is by choosing low-mercury varieties.

Symptoms of methylmercury poisoning primarily affect the nervous system and can include tremors, numbness, impaired vision, and coordination issues. In developing fetuses, exposure can cause neurological developmental impairments.

The mercury content depends on the species and diet, not necessarily whether it's wild or farmed. However, some studies suggest that farmed salmon can have lower mercury levels than wild salmon. Always check guidelines for specific species rather than relying on wild vs. farmed status alone.