When you have beaten the "Bats Tower" chapter it will come to the cutscene where you will meet the catfish again. They will tell you to give them the money that you took out of the vault. After that, you'll only get $10. And when you start to go back to where you started from, the dogfish will break the rope and will start to chase after you. And he will also munch on any of the catfish on the way. And when you get to the small boardwalk there will be a cutscene and the godfish will bust into the wall. But BEFORE you leave the area, go on top of the dogfish and you will see 3 wads of money! Once you pick them all up, pause the game and you will see that you just got $300 more!