Can Babies Still Eat Cod? Understanding the "Silver Cod" Mercury Scare

Recently a story spread widely online: a 2-year-old child ate a children’s “silver cod” product several times a week for eight straight months, and a blood test showed mercury around 27.78 µg/L — clearly above the normal range, requiring medical treatment to remove the mercury.

Many mothers who saw this remembered buying similar products for their own children, and began to blame themselves. Some even said, “I poisoned my child — I’m not a good mother.”

First, don’t panic. This is nobody’s fault, and the fish is not poisonous. The problem lies in confusing fish names, plus eating one type for too long and too often. Once you know how to choose fish and how much to serve each time, there is no need to worry excessively.

A fish "traffic light" for children

Fish is good for children — high-quality protein and DHA support brain and vision development. The key is choosing the right kinds and controlling portions. For children aged 1–3, keep each serving to about 1 liang (roughly 28 grams).

Low mercury · eat often

• Salmon
• True cod (Atlantic cod, Pacific cod, Alaska pollock)
• Mackerel, sardines
• Shrimp, shellfish
• Freshwater fish, farmed fish, small fish

Aim for about twice a week.

Medium mercury · eat less

• Silver cod (Patagonian toothfish, also sold as Chilean sea bass)
• Halibut
• Canned albacore tuna

At most once a week. Don’t rely on it long term or eat it frequently.

High mercury · avoid

• Shark, swordfish, marlin
• Bigeye tuna, bluefin tuna
• Tilefish

Pregnant, breastfeeding and very young children should avoid these as much as possible.

In daily meals, make low-mercury fish the staple and vary the types — don’t eat only one large fish for a long time. Whatever the fish, cook it thoroughly, and never give children raw fish.

First, know this: "silver cod" ≠ true cod

Several different fish are sold under the name “cod,” and they differ greatly.

• True cod — low mercury and suitable for children, including Atlantic cod, Pacific cod and Alaska pollock (walleye pollock). They grow quickly and accumulate little mercury, making them a good choice for baby food.
• Silver cod / black cod — these are actually two large fish, mainly the Antarctic toothfish (also called Chilean sea bass) and sablefish. Neither is a cod in the biological sense; both are large, long-lived deep-sea fish with relatively higher methylmercury.
• Oil fish sold as cod — some sellers pass off oil fish (escolar) as cod. Oil fish contains indigestible wax esters that can cause diarrhea and orange, oily stools. This is different from mercury poisoning.

Remember: when buying “cod” for a child, look for true cod such as Atlantic, Pacific or Alaska pollock. “Silver cod” is fine as an occasional taste, but don’t make it an everyday staple.

How to understand this "elevated blood mercury" case

• The fish itself met standards; the problem was the amount eaten. The children’s silver cod tested at about 0.21 mg/kg of methylmercury, within the national limit (methylmercury ≤ 1.0 mg/kg for carnivorous fish; total mercury ≤ 0.5 mg/kg for ordinary aquatic products).
• “Compliant” does not mean “eat as much as you like.” The 2-year-old ate about 110 grams a week for eight months — far above the recommended 28–56 grams a week for ages 1–3. Long-term buildup is what raised the blood mercury. Even switching to low-mercury true cod, this pattern could still push intake too high.
• Standards for infant and toddler foods are stricter. The national limit for total mercury in canned infant supplementary foods is ≤ 0.02 mg/kg — far below ordinary aquatic products. For babies, choose age-appropriate commercial foods and read the label carefully.
• High blood mercury is not necessarily from fish. A blood test only shows mercury is present; other sources such as rice or other seafood must be ruled out. Follow your doctor’s advice for re-testing and assessment — don’t draw conclusions on your own, and don’t over-blame yourself.

Other everyday sources of mercury

Besides fish, several common household items can also contain mercury.

• Skin-lightening and spot-removing creams — avoid products from unknown sources. Some illegal products add mercury, which the skin can absorb and which damages the kidneys and nervous system; this is a common cause of chronic mercury poisoning in China.
• Folk remedies such as cinnabar and calomel — these contain mercury; do not give them to children by mouth or on the skin. Traditional medicines that include them should be used only under a doctor’s guidance.
• Mercury thermometers and sphygmomanometers — the main risk is after they break, when mercury beads evaporate and are inhaled. Consider switching to electronic thermometers and blood-pressure monitors.

If a mercury thermometer breaks, do not use a vacuum cleaner or broom. Open the windows immediately, collect the beads with gloves, seal them as hazardous waste, and keep ventilating for 24 hours.

If a mercury thermometer breaks

Do this:

1. Get children and pets out, and open the windows.
2. Turn off the air conditioning or heating, and close doors to other rooms.
3. Wear gloves and use a stiff piece of paper to gather the beads.
4. Use a dropper or syringe to pick them up, and place them on a wet wipe.
5. Shine a flashlight at a low angle to find small beads in cracks.
6. Pick up the tiniest beads with tape.
7. Put everything into a sealable bag, tighten it, and treat it as hazardous waste.
8. After cleanup, keep ventilating for at least 24 hours.

If pregnant women or infants are present, call your doctor for advice.

Never do this:

1. Do not use a vacuum cleaner — it blows mercury into vapor that spreads.
2. Do not use a broom — it breaks the beads and scatters them further.
3. Do not pour mercury down a drain — it contaminates pipes and water.
4. Do not touch it with bare hands.
5. Do not walk around wearing clothes or shoes that touched mercury.
6. Do not try to decontaminate or wash carpets or fabric that were contaminated.

Swallowing liquid mercury from a broken thermometer is absorbed very little and usually not an emergency; but if coughing, shortness of breath, or red, painful hands and feet appear, seek medical care promptly.

About the doctor

Dr. Li Yueping
Deputy Director of Pediatrics, Beijing United Family Hospital; Director of the Child Health Department

Book an appointment →

• A message from the doctor: Support parents, help children.
• Areas of expertise:
• 30 years guiding child growth and development, including responsive feeding and sleep support for infants and toddlers (including cow’s-milk-protein allergy) and individualized parenting and development guidance.
• 20 years managing preterm and high-risk infants, including developmental supportive-care guidance, neuro-motor assessment, post-discharge feeding and nutrition guidance, development monitoring, and family-centered early intervention and promotion.

This article is for general health education only and cannot replace an in-person consultation. Please follow your doctor’s advice for your individual situation; for preterm babies, refer to corrected age. The case figures are compiled from public reports; actual values are subject to official information.

References:

1. Guangming Net. A 2-year-old with abnormal blood mercury suspected from eating silver cod: expert interpretation (drawing on the China National Center for Food Safety Risk Assessment and Litchi News). 2026-10-05.
2. Huxiu. Silver cod, true cod and children’s methylmercury intake analysis (species identification, FDA mercury data and child portions). 2026-10-01.
3. National Health Commission, State Administration for Market Regulation. GB 2762—2022 National food safety standard — Limits of contaminants in foods (mercury limits, Table 3).
4. U.S. FDA / EPA. Advice about Eating Fish: For Those Who Might Become or Are Pregnant or Breastfeeding and Children Ages 1–11 Years.
5. CDC / ATSDR. Mercury: evaluating exposure and clinical management. 2012.
6. U.S. EPA. What to Do if a Mercury Thermometer Breaks.
7. Chronic mercury poisoning from skin-lightening cosmetics — case analysis. Occupational Health and Emergency Rescue, 2019.

Source: Beijing United Family Hospital WeChat article, 14 Oct 2026.