The fight starts with Patrick. The frogfish will try to ram you at first. Dodge it by cartwheeling out of the way (because Patrick is so slow). If it hits you, hit the old lady on its tongue. Once you clear the green part of its health bar, it will jump to another platform. It will dig with its tongue and try to hit you. Hit the tongue. Keep repeating this. When the fish jumps to the other platform, the tongue will do a spinning attack. Do a slam on it.