Is there a way to reduce the amount of mercury in fish?

Can't remove mercury: Mercury increases throughout the food chain and is in largest concentrations in carnivorous fish. ('bioaccumulation') the mercury is in the flesh of the fish and cannot be removed through any process. It is best to avoid consumption of certain species known to have high levels of mercury. See http://water.Epa.Gov/scitech/swguidance/fishshellfish/outreach/advice_index.Cfm for more details.

No: Fish with very high potential mercury levels: shark, swordfish, marlin, king mackerel, big eye & ahi tuna, orange roughy & tilefish. Limit intake of yellow fin & white albacore tuna, spanish & gulf maceral, group, bluefish & chilean sea bass. For healthier mercury levels try: crabs, crawdaddies, haddock, flounder, salmon, shrimp, oysters, anchovies, herring, mullet, sole, clams & freshwater trout.