Top 15 Low and High Mercury Fish: Safe for Kids and Pregnant Women

by Nikolai Nikitenko August 13, 2026

Nutrition experts consistently recommend seafood as one of the healthiest foods for kids and pregnant mothers. It is a rich source of vitamins, minerals, omega-3 fatty acids, and complete proteins that support fetal brain development and childhood growth. However, not all seafood is created equal. Studies show that certain types of seafood contain methylmercury — a toxic compound that can impair the development of a fetus' nervous system and affect children under six years old.

The good news: most commonly eaten fish are low in mercury and perfectly safe. The key is knowing which fish to enjoy freely, which to limit, and which to avoid altogether. This guide covers the top 15 low-mercury fish and the high-mercury species to watch out for, with full nutrition details for each.

How Mercury Gets Into Fish

Mercury enters waterways through industrial pollution and natural geological processes. Bacteria in water convert inorganic mercury into methylmercury, which is absorbed by small organisms. As larger fish eat smaller ones, mercury concentrates up the food chain — a process called bioaccumulation. This is why large, long-lived predatory fish like shark and swordfish carry the highest mercury loads, while small, short-lived fish like sardines and anchovies carry very little.

FDA and EPA Guidelines for Mercury in Fish

The U.S. Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) jointly advise:

  • Pregnant women, breastfeeding mothers, and young children should eat 2–3 servings (8–12 oz) per week of low-mercury fish.
  • They should avoid shark, swordfish, king mackerel, tilefish, bigeye tuna, marlin, and orange roughy.
  • They should limit albacore (white) tuna and yellowfin tuna to one serving per week.
  • Canned light tuna (skipjack) is generally considered a low-mercury option.

Fish High in Mercury

Ideally, all seafood contains some mercury. However, some seafood has high levels of mercury while others have minute levels. Fish and seafood with high mercury levels to avoid include:

  • Shark
  • Swordfish
  • Tilefish (Gulf of Mexico)
  • King Mackerel
  • Bigeye Tuna
  • Marlin
  • Orange Roughy

Is halibut high in mercury? Halibut mercury levels are classified as mid-range — they should be consumed in moderation (no more than one serving per week for pregnant women). Other seafood in this mid-range category include:

Top 15 Fish Low in Mercury

1. Salmon

Salmon is one of the most nutritionally complete fish available. The EPA classifies salmon under the very low mercury category, making it one of the safest choices for pregnant mothers and young children. Wild-caught Alaskan salmon is particularly prized for its high omega-3 content. Key nutrients include selenium, biotin, B vitamins (B3, B6, B12), omega-3 fatty acids (EPA and DHA), and complete protein. A 3.5 oz serving of wild salmon provides roughly 2,260 mg of omega-3s — well above the recommended daily intake.

2. Catfish

Catfish is a diverse group of fish recognized by their prominent whisker-like barbels. Common varieties include channel catfish (North America), Mekong giant catfish (Southeast Asia), and Wels catfish (Eurasia). Catfish mercury levels are low, and it is a lean, affordable protein source. Key nutrients: protein, vitamin B-12, phosphorus, selenium, omega-3 fatty acids, magnesium, iron, and zinc. Farm-raised catfish from the U.S. is considered a sustainable choice.

3. Mullet

Mullet is found in coastal temperate and tropical waters worldwide. It has a mild, slightly sweet flavor and is popular in Mediterranean and Southern U.S. cuisines. Mercury levels are low. Key nutrients: Vitamin A, Vitamin B-9 (folate), Vitamin B-3 (niacin), protein, calcium, magnesium, phosphorus, selenium, zinc, and iron. Mullet roe (bottarga) is considered a delicacy in many cultures.

4. Herring

Herring are small, oily fish found in the Atlantic Ocean, the North Pacific, the Baltic Sea, and off South America's south coast. They are one of the richest natural sources of omega-3 fatty acids and vitamin D. Mercury levels are very low. Key nutrients: omega-3 fatty acids, calcium, vitamin D, Vitamin B6, zinc, iron, Vitamin B-12, magnesium, and protein. Herring is commonly available smoked, pickled, or canned.

5. Anchovies

Anchovies are tiny, short-lived fish found in the Mediterranean, Black Sea, and the Indian, Atlantic, and Pacific oceans. Because they are so small and low on the food chain, they accumulate virtually no mercury. They are an excellent source of omega-3 fats, calcium, protein, iron, and zinc. Anchovies are also rich in umami flavor and are used widely in sauces, dressings, and as pizza toppings.

6. Alaska Pollock

Alaska Pollock is a North Pacific marine fish and one of the most sustainably harvested fish in the world — it is the species used in most fish sticks and fast-food fish sandwiches. It can grow up to 3.44 feet and has mild, white, flaky flesh. Mercury levels are low. Key nutrients: lean protein, heart-healthy omega-3 fatty acids, potassium, vitamin B12, and selenium. Alaska Pollock is MSC-certified and considered one of the best sustainable seafood choices.

7. Crayfish

Crayfish (also called crawfish or crawdads) resemble small lobsters and are found in freshwater bodies, swamps, and streams across North America, Europe, and Australia. Mercury levels are very low. Key nutrients: B vitamins, lean protein, calcium, zinc, phosphorus, and magnesium. Crayfish are a staple of Cajun cuisine and are typically boiled with spices.

8. Haddock

Haddock is a popular North Atlantic whitefish closely related to cod. An adult haddock can grow to 1.1 meters. Mercury levels are low. Key nutrients: potassium, sodium, vitamin B12, Vitamin D, calcium, iron, magnesium, Vitamin A, and Vitamin C. Haddock is the traditional fish used in British fish and chips and Scottish smoked haddock (Finnan haddie). It is widely available fresh, frozen, and smoked.

9. Sardines

Sardines are small, oily fish found in warm coastal waters off India, Indonesia, California, and Japan. Like anchovies, their small size and short lifespan mean they accumulate very little mercury. Mercury levels are very low. Key nutrients: vitamin B12, phosphorus, omega-3 fatty acids, selenium, calcium, vitamin B2, iron, and protein. Canned sardines with bones are one of the best dietary sources of calcium available.

10. Hake

Hake are deep-sea fish found mainly in the North East Atlantic and Pacific Oceans. They are a popular seafood delicacy in Europe, particularly in Spain and Portugal, prized for their medium-flake white meat and mild flavor. Mercury levels are low. Key nutrients: lean protein, calcium, Vitamin A, Vitamin C, iron, sodium, and omega-3 fatty acids. Pacific whiting (a type of hake) is one of the most abundant and sustainably managed fish on the U.S. West Coast.

11. Tilapia

Tilapia is a mild-flavored freshwater fish commonly found in lakes, ponds, and streams, and widely farmed around the world. Mercury levels are very low. Key nutrients: lean protein, omega-3 fatty acids, vitamin D, B vitamins, magnesium, and potassium. Note: tilapia has a higher ratio of omega-6 to omega-3 fatty acids compared to fatty fish like salmon, so it is best consumed as part of a varied diet.

12. Oysters

Oysters are bivalve molluscs that thrive in salty marine and brackish water. They are filter feeders, which means they naturally purify the water around them — making oyster farming one of the most environmentally beneficial forms of aquaculture. Mercury levels are very low. Key nutrients: protein, calcium, magnesium, iron, vitamin B-12, zinc, potassium, vitamin C, sodium, copper, and selenium. Oysters are one of the best dietary sources of zinc.

13. Freshwater Perch

Freshwater perch is found in lakes, ponds, and rivers across North America and Europe. It has firm, mild white flesh and is popular among anglers. Mercury levels are low. Key nutrients: phosphorus, vitamin D, vitamin C, iron, lean protein, potassium, and omega-3 fatty acids. Yellow perch from the Great Lakes is particularly well-regarded for its flavor.

14. Trout

Trout are found in cool, clear freshwater bodies like lakes, rivers, and mountain streams. Rainbow trout is the most commonly farmed variety and is considered a best-choice sustainable seafood by the Monterey Bay Aquarium's Seafood Watch program. Mercury levels are low. Key nutrients: sodium, calcium, iron, complete protein, vitamin B12, vitamin C, potassium, manganese, and phosphorus. Trout has a delicate flavor similar to salmon and is excellent baked, grilled, or pan-seared.

15. Whitefish

Whitefish is a broad fishery term covering multiple species including cod, whiting, haddock, and Caspian kutum. Most live on or near the sea floor and have lean white flesh. Mercury levels are low. Key nutrients: lean protein, healthy fats, potassium, vitamins (B12, D), selenium, magnesium, and calcium. Whitefish is highly versatile and works well in soups, chowders, tacos, and baked dishes.

Quick Mercury Reference Chart

Use this at-a-glance guide when shopping or ordering at a restaurant:

  • Very Low Mercury (eat freely): Salmon, Sardines, Anchovies, Herring, Oysters, Tilapia, Crayfish, Catfish, Alaska Pollock
  • Low Mercury (2–3 servings/week): Haddock, Trout, Freshwater Perch, Mullet, Hake, Whitefish
  • Moderate Mercury (limit to 1 serving/week): Halibut, Sablefish, Lobster, Albacore Tuna, Rockfish, Bluefish
  • High Mercury (avoid if pregnant or feeding young children): Shark, Swordfish, King Mackerel, Tilefish, Bigeye Tuna, Marlin, Orange Roughy

Frequently Asked Questions

What fish is lowest in mercury?

Salmon, sardines, anchovies, herring, oysters, tilapia, crayfish, catfish, and Alaska Pollock are among the lowest in mercury. These are all safe for pregnant women and young children when consumed in recommended amounts (2–3 servings per week).

Is halibut high in mercury?

Halibut falls in the moderate mercury category. Pregnant women and young children should limit halibut to no more than one serving per week. It is not in the high-mercury "avoid" category, but it should not be eaten as freely as salmon or sardines.

Can pregnant women eat tuna?

It depends on the type. Canned light tuna (skipjack) is low in mercury and generally safe at 2–3 servings per week. Albacore (white) tuna is moderate and should be limited to one serving per week. Bigeye tuna (common in sushi) is high in mercury and should be avoided during pregnancy.

How much fish should pregnant women eat per week?

The FDA and EPA recommend that pregnant women, breastfeeding mothers, and young children eat 2–3 servings (8–12 oz total) of low-mercury fish per week. This provides important omega-3 fatty acids (DHA and EPA) that support fetal brain and eye development.

Is salmon safe for kids?

Yes. Salmon is classified as very low in mercury by the EPA and is one of the best fish for children. It is rich in DHA omega-3 fatty acids, which are critical for brain development. Wild-caught Alaskan salmon is the top choice for both nutrition and sustainability.

What is the safest seafood for toddlers?

The safest seafood for toddlers includes salmon, sardines, tilapia, catfish, Alaska Pollock, and oysters — all very low in mercury and rich in nutrients. Introduce seafood in age-appropriate textures (flaked, not whole pieces) and watch for any allergic reactions.

Does cooking fish reduce mercury?

No. Cooking does not reduce mercury levels in fish. Mercury is bound to the fish's muscle tissue and is not destroyed by heat. The only way to reduce mercury exposure is to choose low-mercury species and follow the recommended serving guidelines.

Is farmed salmon lower in mercury than wild salmon?

Both farmed and wild salmon are very low in mercury. Wild-caught Alaskan salmon tends to have slightly higher omega-3 levels, while farmed Atlantic salmon may have higher overall fat content. Both are excellent, safe choices for pregnant women and children.

What seafood should I avoid during pregnancy?

Avoid shark, swordfish, king mackerel, tilefish (Gulf of Mexico), bigeye tuna, marlin, and orange roughy. These fish are high in mercury and can harm fetal neurological development. Also avoid raw or undercooked seafood (sushi, oysters on the half shell) due to the risk of foodborne illness.

Are shrimp and crab low in mercury?

Yes. Shrimp and crab are both very low in mercury and are among the most popular seafood choices for pregnant women. They are safe to eat 2–3 times per week as part of a balanced diet.

What is bioaccumulation of mercury in fish?

Bioaccumulation (also called biomagnification) is the process by which mercury concentrates as it moves up the food chain. Small fish absorb mercury from water and plankton. Larger fish eat many small fish, accumulating higher mercury levels. Top predators like shark and swordfish, which eat many large fish over long lifespans, end up with the highest mercury concentrations.

Is canned salmon safe during pregnancy?

Yes. Canned salmon is very low in mercury and is one of the most convenient and affordable ways to get omega-3 fatty acids during pregnancy. Choose wild-caught Alaskan salmon when possible. Canned salmon with bones is also an excellent source of calcium.

How do I know if a fish is sustainable and low in mercury?

Look for certifications like the Marine Stewardship Council (MSC) blue label for wild-caught fish, or the Aquaculture Stewardship Council (ASC) label for farmed fish. The Monterey Bay Aquarium's Seafood Watch app also provides real-time sustainability ratings. Generally, small, fast-reproducing fish (sardines, anchovies, herring) are both low in mercury and highly sustainable.

Can I eat sushi while pregnant?

Most health authorities advise pregnant women to avoid raw fish due to the risk of listeria, salmonella, and other pathogens. Cooked sushi rolls (shrimp tempura, crab, cooked salmon) made with low-mercury fish are generally considered safe. Consult your healthcare provider for personalized guidance.

What are the symptoms of mercury poisoning from fish?

Symptoms of methylmercury poisoning include numbness or tingling in hands, feet, or around the mouth; muscle weakness; difficulty walking or speaking; vision or hearing impairment; and in severe cases, cognitive impairment. In fetuses and young children, even low-level exposure can affect neurological development. If you are concerned about mercury exposure, consult your doctor.

Conclusion

Mercury in fish is a real concern, but it should not discourage you from eating seafood — quite the opposite. The vast majority of commonly eaten fish are low in mercury and deliver exceptional nutritional benefits, especially for pregnant women and growing children. Focus on the low-mercury stars: salmon, sardines, anchovies, herring, Alaska Pollock, tilapia, and oysters. Limit moderate-mercury fish to one serving per week, and avoid the high-mercury species entirely during pregnancy and early childhood. When in doubt, refer to the FDA/EPA guidelines and choose wild-caught or sustainably farmed options from trusted sources like Global Seafoods.

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