Flat fish have the most extreme bone structure of all fish. For the first two weeks of their lives they look like any other baby fish. Then something begins to go awry. The face distorts and one eye starts to shift, moving around the head to join the other. It is the beginning of a bizarre transformation as the fish soon begins to swim on its side. The full makeover takes less than a week and the results are fixed for life. The flat fish is now perfectly adapted to life on the sea bed. Its body shape and colouring mean it can keep a low profile. This is handy for hiding from predators or creeping up on prey.