Pelagic fish contain, on average, ten times more methylmercury than offshore fish. Avoid overconsumption of large pelagic oily fish such as shark, tuna and swordfish, such as sardines, wild mahi-mahi and mackerel. Rainbow fish and salmon can be steamed, marinated in vinegar, and so on. Pelagic fish, that is, in the ocean in addition to sharks, non-meat-eating fish, they take the sea microorganisms as the main source of food.