Look on the map
his in a room on the ceiling
The room with the Deku Toad, the mini boss.
in the main room
If you want to find the BOSS for the Lakebed Temple on Twilight Princess, you have to get the BIG KEY and then go to the room with the giant swiveling staircase, and just jump into the water. The BOSS DOOR is level with the water surface under the swiveling staircase. This BOSS is the coolest one so far. -Caveman1593
Look on your map. There is a room directly above the chest. You could hookshot a medallion and lower yourself to the chest.
kill the lakebed temple boss or collect enough heart pieces
The Frog Toad is the miniboss of the Lakebed Temple. After defeating it, you get the Clawshot, which is the dungeon item.
After defeating the Deku Toad, the miniboss of the Lakebed Temple, a chest will appear. This chest is where the Clawshot is.
the desert temple Arbiter's Grounds
In the Lakebed temple/ water temple.
You have to go to the room where the water is held, go up the winding ramp and let loose the water from the room.
When you get the clawhook,go to the rotating staircase room and clawhook to the big light thing at the centre of the ceiling(there are targets above the light to grapple to)On the light there is a chest containing a piece of heart.WALK off the light,dont jump and drop down from there.You should be at the level with the boss room. This saves you raising the water level.