Is the Filet-O-Fish Actually Fish?

The Filet-O-Fish is one of the most famous items on the McDonald's menu. Before the advent of its fishy schtick, the fast-food giant only sold burgers, fries, milkshakes, and various drinks like coke, root beer, milk, and coffee. These classic items served the chain well for well over a decade. But as the franchise expanded, so did the needs of the fast-food-loving public, and the Filet-O-Fish caught our collective attention—hook, line, and sinker. But how much fish is actually in it? And is it even fish?