Hey, its not true. what matters is how you clean your fish and some fish are very high in mecury, some fish that contain mercury are: macrel, Tuna, shark and many more. so as i said b4 it doesnt matter where you buy your fish.... You can becareful for spoit fish in the local market, to be on safer side go to the stores to buy your fish,e.g lulu, carefour,giant store e.t.c