How do you get to the boss room in the water temple in ocarina of time?

The water temple is a long and difficult dungeon, so you should refer to an internet walkthrough for help in getting through it. You must find Shadow Link and defeat him to get the Longshot. The Longshot can get you to a previOSly inacessible area that the boss lies in. Use the Longshot to shoot at it's core and slash at it's core to kill it.