I accidently taught my angelfish a trick. It's not an exciting trick but it's the only one they know.
I was holding a pinch of food over the tank preparing to drop it in when my son walked in the room and started talking to me. I turned around to answer, and the fish jumped up and grabbed the food from my fingers. I was a little taken aback at first, but we've made a game of it. They will jump up whenever I put my hands over the open tank, and have learned to hop up and get treats such as dried bloodworms from a floating log - the kind designed for aquatic turtles.