When steaks are cut from the central body of the fish, the flaps of flesh around the stomach cavity can be tied in a round to make them look more presentable. Here, salmon is shown.
With a small knife, cut the bones lining the stomach cavity away from the flesh. Cut around the backbone with the point of the knife and remove it.
Curl the two flaps of flesh inward to form a heart shape and tie it with string, or secure it with toothpicks to hold the shape.