In Merge Fish, your goal is to merge three or more fish into one larger fish. Each time you tap on a sidefish, they enter the puzzle board and move around until something happens to them (they cannot escape their fate). Later in the game, you have keep track of what color each individual fish is so that they can be merged together without fail. You should set them in a correct order and let them merge until it becomes its own new color-the bigger question being: how do you figure out which colors will blend?
How To Play Merge Fish