Natural Resources Defense council's List of levels of Mercury Fish

LEAST MERCURY
Enjoy these fish:
Anchovies
Butterfish
Catfish
Clam
Crab (Domestic)
Crawfish/CrayfishCroaker (Atlantic)
Flounder*
Haddock (Atlantic)*
Hake
Herring
Mackerel (N. Atlantic, Chub)
Mullet
Oyster
Perch (Ocean)
PlaicePollockSalmon (Canned)**
Salmon (Fresh)**
Sardine
Scallop*
Shad (American)
Shrimp*
Sole (Pacific)
Squid (Calamari)
Tilapia
Trout (Freshwater)
Whitefish
Whiting


MODERATE MERCURY - Eat six servings or less per month :
Bass (Striped, Black)
CarpCod (Alaskan)*
Croaker (White Pacific)
Halibut (Atlantic)*
Halibut (Pacific)
Jacksmelt(Silverside)
Lobster
Mahi Mahi
Monkfish*
Perch (Freshwater)
Sablefish
Skate*
Snapper*
Tuna (Cannedchunk light)
Tuna (Skipjack)*
Weakfish (Sea Trout)


HIGH MERCURY - Eat three servings or less per month :
Bluefish
Grouper*
Mackerel (Spanish, Gulf)
Sea Bass (Chilean)*
Tuna (Canned Albacore)
Tuna (Yellowfin)*


HIGHEST MERCURY - Avoid eating :
Mackerel (King) Marlin*
Orange Roughy*
Shark*
Swordfish*
Tilefish*
Tuna(Bigeye, Ahi)*