Fish That May Contain Mercury

When mercury builds up to toxic levels in the human body, it can cause permanent neurological damage. If you are pregnant, mercury is dangerous to your developing fetus and later to your breastfeeding baby. A fetus exposed to mercury during pregnancy is especially likely to suffer mild to severe nervous system damage. In the same way, young children who eat a lot of fish containing mercury can suffer permanent brain damage.

Mercury occurs naturally in the environment and also as a result of industrial pollution. It is in our water, air, soil, and food. Fish are the most common source of mercury in the human diet. You can best protect your child from mercury exposure by avoiding high-mercury fish before and during pregnancy and when breastfeeding and choosing foods for your young child.

The U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) have issued the following advisory for pregnant women, women of childbearing age, nursing mothers, and young children: footnote 1

  • Do not eat shark, swordfish, king mackerel, or tilefish. These all contain high levels of mercury.
  • Eat up to 12 oz (340 g) a week (two average meals) of a variety of fish and shellfish that are lower in mercury.
    • Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
    • Another commonly eaten fish, albacore ("white") tuna, has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 oz (170 g) a week (one average meal) of albacore tuna.

Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 oz (170 g) a week (one average meal) of fish caught from local waters, but don't eat any other fish during that week. Also check the U.S. Environmental Protection Agency (EPA) website for mercury advisory updates at

Mercury will slowly leave the body over time in the urine, feces, and breast milk. If you are concerned about your own or your child's mercury level, talk to your doctor or local health department about testing.


  1. U.S. Food and Drug Administration (2004). What you need to know about mercury in fish and shellfish: 2004 EPA and FDA advice for women who might become pregnant, women who are pregnant, nursing mothers, young children. Available online:

ByHealthwise Staff
Primary Medical Reviewer Sarah Marshall, MD - Family Medicine
Adam Husney, MD - Family Medicine
Specialist Medical Reviewer Kirtly Jones, MD - Obstetrics and Gynecology

Current as ofJune 14, 2016