The Filet-O-Fish is a fish sandwich served at McDonald's. It is also referred to as the FishMac or McFish in non-English speaking countries. The sandwich consists of a breaded and fried whitefish filet topped with pickled relish, half a slice of cheese, and tartar sauce, all on a steamed bun. It was invented in 1962 by Lou Groen, an early McDonald's franchisee based in Cincinnati, Ohio. While the fish composition of the sandwich has changed through the years to satisfy taste and supply shortcomings, the framework of its ingredients have remained the same; a fried fish filet patty, steamed bun, tartar sauce, and pasteurized processed American cheese.