The issue: Certain fish may contain high levels of mercury, which can contribute to developmental delays. Farm-raised fish may be contaminated with PCBs (cancer-causing agents) and other toxins.
What's okay: You can safely consume up to 12 ounces a week of wild salmon (not farm-raised), sea bass, shrimp, sole, snapper, flounder, catfish, cod, haddock, sardines, tilapia, ocean perch, and pollack. Restrict tuna consumption to the "chunk light" canned variety and no more than six ounces a week. Canned or shelf-stable salmon is safe.
What to avoid: Swordfish, shark, king mackerel, tilefish, and fresh (as well as canned albacore) tuna; raw sushi and raw shellfish; refrigerated smoked seafood such as lox, trout, and whitefish (unless cooked as an ingredient in another dish).