What is the theme of the fisherman and his wife story

The moral in the fable of the fisherman and his wife was based in being happy and greatful if something has been obtained for a good work and avoiding the greed if you get something. In it you can see two positions, one exposed in the fisherman who from the beginning asked for nothing in exchange for having saved the fish's life and the opposite in his wife who was always greedy and sended his husband back to the fish always asking for more.