High levels of mercury
Mercury may affect the nervous system, and some fish contain more mercury than others.
Alligator
Make sure it is well cooked.
Bass
Moderate levels of mercury have been detected in this fish. Avoid where possible but it should be fine in very limited quantities.
Bluefish
There are moderate levels of mercury in this fish, and you should avoid if possible. It should be fine in very limited quantities.
Bombay Duck
Unsafe levels of mercury have reportedly been found in Bombay Duck found off the shore of India. Be sure to double check the source.
Crocodile
Make sure it is well cooked.
Kingfish (King Mackarel)
This is not recommended for pregnant women due to the levels of mercury found in the fish's system.
Lamprey
High levels of mercury have been detected in lampreys.
Mahi Mahi (Dorado)
Moderate levels of mercury mean you shouldn't consume more than six six-ounce portions per month.
Patagonian Toothfish (Chilean Seabass)
There are moderate levels of mercury in this fish, and you should avoid if possible. It should be fine in very limited quantities.
Portuguese Dogfish (Siki)
Don't eat more than 150g a week.
Sablefish (Black Cod)
There are moderate levels of mercury in this fish, and you should avoid if possible. It shouldn't be an issue in strictly limited amounts.
Unsafe