Fish is a great way to add health benefits at the dinner table. The USDA recommends we eat seafood twice a week while aiming to eat a variety of seafood. But not all fish are good for you and some may be especially dangerous if you are pregnant or nursing. Nearly all fish and shellfish contain traces of mercury. Mercury is a toxic metal that can lead to neurological and kidney damage, and is especially dangerous to pregnant women and developing children as it can cause birth defects. Depending on the fish, the mercury levels may be low enough for even pregnant and nursing woman to enjoy. That’s because eating it during pregnancy may lower the risk of high blood pressure disorders and preterm birth, and lead to better brain development, language, and communication skills in children, says the U.S. Dietary Guidelines Advisory Committee’s 2020 Scientific Report. So here are the healthiest fish to eat, not only for nutrition but for sustainability as many fish species are overfished. Oysters top the healthy list. One serving delivers more than 1,000 milligrams of good-for-you omega-3s, is chock full of vitamin B12 and zinc (you get well over double your daily needs), and nearly 40% of your daily iron dose. Be cautious when eating raw oysters, especially those from warmer waters, as they may contain bacteria that can cause serious illnesses. A single serving of Sablefish delivers at least 1,000 milligrams of omega-3s and it's a good source of vitamin B. Salmon is low in mercury and high in omega-3s and found at nearly every grocery store. Shrimp caught off the coasts of the U.S. and Canada, is easy to cook, mild in flavor, packed with protein, is practically fat-free and chock full of selenium. Rainbow trout caught in the United States and albacore and skipjack tuna are good choices too. Stay away from Bluefin tuna, Orange Roughy, Atlantic Halibut and swordfish, which all contain high levels of mercury and are overfished.