How do you get past the water dragon on okami?

Answer 1

Well if your not at the dragon palace then you'll need to go to catcall tower first. Which to get there you'll need to get the orca to take you there. And you find out how by talking to the kid getting hit by the other kids. Then after you get the new power from the catcall tower you can get to star watchers cape and make the whirlpool galaxy appear. After that you ride the orca to the whirlpool that appears in the water after the whirlpool galaxy appears. When you're at the dragon palace you go forward into the building and keep going till you get to the elevator and it will take you up and you'll talk to the dragonian queen and she'll give you something to allow you in another door down stairs. Find the door with a picture of a dragon on it and you'll find the water dragon sleeping with its mouth open and that's it you'll find out what to do from there.

Answer 2

In the game, you never fight that water dragon. It's a good guy, just driven mad by various things: monsters and the Fox Rods that are embedded in it's belly.