Omega-3 and fish

How much fish should I eat while pregnant?

By GyroscopeUpdated November 15, 20266 sources

The FDA’s advice is 8 to 12 ounces of fish a week while you’re pregnant or breastfeeding. That’s 2 to 3 servings of 4 ounces from its Best Choices list, the fish lowest in mercury, or 1 serving from its Good Choices list. Salmon, sardines and trout are Best Choices, and they bring the most omega-3 of the fish people usually buy.

Plenty of people cut fish out completely when they find out they’re pregnant, because mercury is the one thing they’ve heard about it. The FDA’s advice goes the other way. It says fish give a baby nutrients for brain development, including the omega-3 fats DHA and EPA, and that “moderate scientific evidence” shows eating fish in pregnancy can help a baby’s cognitive development. The 2026 US Dietary Guidelines also name “low-mercury omega-3–rich seafood (e.g., salmon, sardines, trout)” for pregnant women.

What we’d do: two or three palm-sized servings a week of salmon, sardines, trout or herring. They’re all low in mercury and high in omega-3. Canned light tuna counts toward the ounces, but it brings very little omega-3. The FDA’s own measure for a serving is the palm of your hand, which is about 4 ounces for an adult.

Which fish are on the lowest-mercury list?

The Best Choices list is long, and most of the fish in a supermarket are on it. Among them are salmon, sardines, freshwater trout, herring, anchovies, Atlantic mackerel, cod, haddock, pollock, tilapia, catfish, flounder, sole, shrimp, scallops, crab, clams, oysters and canned light tuna (skipjack included).

The Good Choices list is for one serving a week, with no other fish that week. It includes albacore (white) tuna, canned or fresh, yellowfin tuna, halibut, mahi mahi, snapper, grouper, striped bass, Spanish mackerel and Chilean sea bass.

Seven fish are the ones to skip, since they carry the most mercury: king mackerel, marlin, orange roughy, shark, swordfish, tilefish from the Gulf of Mexico and bigeye tuna.

Which fish bring the most omega-3?

Low in mercury and high in omega-3 are two different lists, and they only partly overlap. Cod and shrimp are Best Choices, but 8 ounces a week of either gives you almost no EPA or DHA. Salmon gives you about ten times what canned light tuna does.

At 12 ounces a week, the top of the FDA’s range, farmed salmon comes to about 1,000 mg of EPA and DHA a day and sardines about 480 mg. Mixing the two over a week lands you between those.

What about fish oil capsules?

The FDA’s fish advice doesn’t cover supplements, and the 2026 guidelines say to talk to your health care professional about a daily prenatal vitamin. Whether you need a fish oil or algae oil capsule on top of the fish is a question for your midwife or doctor. The omega-3 counter below has a pregnancy switch, and it doesn’t work out capsule doses in pregnancy.

Fish someone caught for you

Larger carp, catfish, trout and perch from local waters are more likely to carry mercury or other contaminants. The FDA says to check for a local fish advisory first, and if there isn’t one, to eat only one serving of that fish and no other fish that week.

Breastfeeding and young children

The same 8 to 12 ounces a week applies while you’re breastfeeding. For children, the FDA suggests 2 servings a week from the Best Choices list, with smaller servings by age: about 1 ounce at age 1 to 3, 2 ounces at 4 to 7, 3 ounces at 8 to 10 and 4 ounces from 11. When the advice changes covers the other times the fat advice is different, and which fish has the most omega-3? ranks the common fish.