Fish is good for you! It’s high in protein, low in fat, and may even help brain development.
But we keep hearing news reports about mercury and other poisonous heavy metals in fish.
Large, predatory fish, high on the food chain, are the ones that accumulate mercury. Children and pregnant women should avoid these fish that are high in Mercury: swordfish, king mackerel, fresh tuna, tilefish, orange roughy, marlin, and both ahi and bigeye tuna.
But young children might benefit from a couple servings a week of fish that are significantly lower in mercury: “Light” tuna (skipjack), salmon, catfish, tilapia, herring, sardines and trout. Also, shellfish such as shrimp, scallops, and oysters are lower in mercury, and are also considered healthy.
— Dr. Epstein