Look on your map. There is a room directly above the chest. You could hookshot a medallion and lower yourself to the chest.
in the lakebed temple
in the main room
No he is not in the temple but after you beat Lake Bed temple he is in a cut scene after you beat the temple so WATCH CAREFULLY.
you need to go to the lakebed temple in lake hylia
kill the lakebed temple boss or collect enough heart pieces
The frog miniboss is in the Lanayru province, in the Lakebed Temple. See 'related links' for a map; the miniboss is in room 9.
his in a room on the ceiling
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
It's at the bottom of Lake Hylia. You should have gotten the Zora Armor by now. From there, put it on and just go the place marked on your map.
Commonly, after defeating a miniboss, you get an item, and that item is probably going to be used for at least the rest of the Temple. You get the clawshot at the Lakebed Temple, after the miniboss, which is the Deku Toad. You'll notice it on the ceiling, in a circular room.
After beating lakebed temple, you will have to beat the temple in the desert. Though it isn't the end just yet.
For the first part, use the clawshoot to pull Morpheel's eye out. For the second part, chase after him and use the clawshhot to pull yourself to his eye and attack it.