Just to add to Idza's list, you should also avoid Atlantic Salmon, Chilean Sea Bass, Orange Roughy and Marlin. These are also fishes high in mercury content. Also good to avoid raw fish and shellfish, and refrigerated smoked seafood. And here are some FDA approved fishes, safe for consumption during pregnancy (up to 12ounces, around 340g, a week): Catfish, Pollock, Salmon, Shrimp, Canned light tuna For more information on how to eat right during pregnancy: http://sg.theasianparent.com/pregnancy_diet_donts/
Basically any of the fishes that are high in mercury content and they are usually the deep sea fishes. This also includes any kinds of fish that are served raw as there is a chance of being infected with the salmonella bacteria. It is not harmful to baby but can cause serious food poisoning for mummies that leads to dehydration. http://sg.theasianparent.com/pregnancy_diet_donts/
I will avoid fishes that are proven to be high in mercury level such as shark, mackerel. There is a list of fishes that are safe to be consumed (low mercury level) in the figure shown.
Avoid shark, swordfish, mackerel, tilefish because of their high mercury content which have been linked to developmental delays and brain damage.
Should avoid large deep-sea fishes like shark, swordfish, king mackerel and tilefish.
thanks