During gameplay, press Select to access the controller screen, and then enter the following codes.
Creatures Fly Off Screen: Press and hold L, and press X, X, X, X, A, X, X, X, X, and then release L.
Replace pearls with coins: Press and hold L, and press X, A, X, X, X, A, X, X, and then release L.
Destroyable Creatures: You can destroy crabs, puffer-fish, guard fish, piranhas, electric eels, and angler fish. You cannot destroy jellyfish, sea urchins, bus fish, and long eels.
Chapter 3: Pearls: If you attack a puffer fish, many pearls will come out.
Chapter 9: Avoid being caught: To avoid being caught by police fish, go into houses until the cops pass.
Chapter 9: Staying hidden: When you must sneak around the fish with lights on their heads or the ones with torches, there are some tables with cloths on them that you can go under without being detected.
