Fish and Mercury While Trying to Conceive: What to Eat and What to Skip

Fish advice tends to arrive as a list of fears. Mercury, parasites, "don't eat tuna." The result is that many people trying to conceive quietly stop eating seafood altogether, which throws out a food the same federal agencies actively recommend. The goal of this guide is narrower and more useful: show you which fish to buy, how much, and what to skip, using the categories the FDA and EPA actually publish.

Contents

• Who the FDA/EPA advice is written for
• The three lists, in full
• The tuna question
• Why eating fish still matters before pregnancy
• What the fertility studies found for both partners
• Locally caught fish, sushi and smoked salmon
• A sample week

Who the FDA/EPA advice is written for

The FDA and EPA "Advice about Eating Fish" is addressed to people who might become pregnant, people who are pregnant or breastfeeding, and parents feeding young children. The agencies last revised the advice in October 2021, and the FDA's page was most recently updated in 2024. That first group matters for anyone trying to conceive: the advice doesn't switch on with a positive test. It is meant to be your normal pattern in the months before.

The reason is mercury. The EPA describes methylmercury exposure as happening most commonly when people eat fish and shellfish with higher levels, and says unborn babies are the most vulnerable because their brains and nervous systems are still developing. Choosing lower-mercury fish before you conceive means you don't have to change anything once you are pregnant.

A serving in the advice is 4 ounces for adults. The FDA suggests using the palm of your hand as a rough guide.

The three lists, in full

A few practical notes on reading the table:

• The Best Choices list is long and cheap. Canned salmon, sardines, frozen pollock, shrimp, tilapia, cod and canned light tuna are all on it. You don't need fresh wild fish to follow this advice.
• Atlantic mackerel and Pacific chub mackerel are Best Choices; king mackerel is on the avoid list, and Spanish mackerel is a Good Choice. The common name matters, so check the label.
• Tilefish appears twice. Atlantic tilefish is a Good Choice. Tilefish from the Gulf of Mexico is on the avoid list.
• Chilean sea bass and halibut are Good Choices, not Best. These are common restaurant fish, so a restaurant meal of either can be your one Good Choices serving for that week.

The tuna question

Tuna causes more confusion than any other fish because "tuna" covers several species with different mercury levels. Here is how the FDA/EPA lists sort them:

• Canned light tuna, including skipjack: Best Choices.
• Albacore ("white") tuna, whether canned, fresh or frozen: Good Choices.
• Yellowfin tuna: Good Choices.
• Bigeye tuna: Choices to Avoid. Bigeye often shows up as sushi or tuna steaks, and menus don't always name the species. If you can't tell what you're getting, choose something else.

So a tuna sandwich made with canned light tuna fits easily into a Best Choices week. If you prefer albacore, treat it as your single Good Choices serving.

Why eating fish still matters before pregnancy

The FDA's advice is not only a list of limits. It recommends fish because it supplies nutrients that support a baby's brain development: omega-3 fats (DHA and EPA), iron, choline and, during pregnancy, iodine. Fish also provides protein, vitamin B12, vitamin D and selenium. The FDA notes moderate scientific evidence that eating fish during pregnancy can help a baby's cognitive development.

The NIH Office of Dietary Supplements summarizes a systematic review of 29 cohort studies, covering more than 102,000 mother-and-child pairs, in which eating about 4 ounces of seafood a week during pregnancy was associated with better neurocognitive development in children. The same fact sheet notes that many pregnant women eat less than the recommended 8 to 12 ounces a week. Building the habit before conception makes it far easier to keep during pregnancy, when nausea and food aversions often narrow the menu.

If you're curious about where else the nutrients in fish show up, our vitamin B12 guide covers one of them in detail, and the winter fertility grocery list shows how canned and frozen fish fit into a practical weekly shop.

What the fertility studies found for both partners

The FDA/EPA advice is about protecting a pregnancy. A separate, smaller body of research has asked whether eating seafood is linked to how quickly couples conceive. It's observational, so it shows associations, not proof, but it is consistent enough to be worth knowing.

The LIFE study: seafood, both partners, and time to pregnancy

In a study of 501 couples planning pregnancy in Michigan and Texas, published in the Journal of Clinical Endocrinology & Metabolism in 2018, both partners logged their seafood intake daily. Among couples who ate at least two servings of seafood a week, 92% were pregnant within 12 months, compared with 79% of couples who ate less. Couples who ate more seafood also reported more frequent sex, but the researchers said that didn't fully explain the difference. The lead author's takeaway was that the male partner's diet mattered as well as the female partner's.

A Dutch preconception cohort

A 2025 study in the American Journal of Clinical Nutrition followed 830 women and 651 men from before or around conception in the Netherlands. In women, higher omega-3 intake (particularly DHA and ALA) was associated with higher fecundability, meaning a higher chance of conceiving each cycle. In men, seafood intake was not associated with fertility, though nuts and seeds were (we cover that in our walnuts and sperm quality guide).

For male partners, fish also fits the overall eating pattern in our male fertility diet plan. The mercury lists are written for women and children, but there's no downside to a male partner choosing from the same Best Choices list, and shared meals are easier to plan.

Locally caught fish, sushi and smoked salmon

Fish you or your family catch

Fish from local lakes, rivers and coastal waters aren't covered by the national lists. The FDA advises checking local fish advisories, which states, territories and Tribes issue (the EPA keeps a contact list). If there is no advisory for that water, the FDA's rule is to eat only one serving of that fish and no other fish that week. The FDA also notes that larger carp, catfish, trout and perch are more likely to carry advisories.

Sushi and raw fish

Mercury isn't the only consideration once you're pregnant. FoodSafety.gov advises avoiding raw or undercooked seafood, such as sushi, sashimi, raw oysters, clams, scallops and ceviche, during pregnancy because of parasites and germs including Listeria. Because you may not know you're pregnant for the first couple of weeks after conception, it's worth asking your clinician how to handle raw fish while you're actively trying if sushi is a regular part of your diet.

Smoked fish

The same guidance says not to eat refrigerated smoked seafood (such as lox or smoked whitefish from the deli case) during pregnancy unless it's cooked in a dish to 165°F. Canned or shelf-stable smoked seafood is fine. All other seafood dishes should reach 145°F.

Two sample weeks that follow the advice

The FDA/EPA amounts are alternatives: in a given week, either eat 2 to 3 servings from Best Choices, or eat 1 serving from Good Choices. Two ways that can look in practice:

Most people find the Best Choices week easier and cheaper to repeat. Canned and frozen options make it realistic even when fresh fish is expensive or hard to find.

If you or your partner are also weighing other parts of the diet, our guides to ultra-processed food and fertility and protein powder while TTC cover two of the most common questions we get after fish.

Sources

• U.S. Food and Drug Administration and Environmental Protection Agency. Advice about Eating Fish (revised October 2021). fda.gov
• U.S. EPA. Health Effects of Exposures to Mercury. epa.gov
• U.S. EPA. Choose Fish and Shellfish Wisely (local fish advisories). epa.gov
• NIH Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. ods.od.nih.gov
• FoodSafety.gov. People at Risk: Pregnant People. foodsafety.gov
• Gaskins AJ, et al. Seafood intake, sexual activity, and time to pregnancy. J Clin Endocrinol Metab. 2018. Summary: Healio
• Schipper MC, Jaddoe VWV, Bekkers EL, Mulders AGMGJ, Gaillard R. Dietary intake of polyunsaturated fatty acids, their food sources and fertility in females and males. Am J Clin Nutr. 2025;121(6):1354–1364. Erasmus University