
All you have to do is go thru the side-passage in King Zora's room, and talk to the Zora there, she will ask you to play a game, and all you have to do is dive off the top of the waterfall and collect all the rupees. Once done, you will get the Silver Scale.
Also, make your way around the ledge along the wall (straight
from the entrance) and you will come to King Zora's room, which you will need to visit if
you are here for your first time during your game. He will inform you that Princess Ruto has
gone missing (she has a bad habit of doing this, believe me) he doesn't exactly ask you to
find her, but this is Zelda, and it is Link who is the hero and therefore has a responsibility
to act like a hero. Visit Lake Hylia next, and once
you have what you need, come back and show it to the King, who will move aside for you to
enter Zora's Fountain, and subsequently, Jabu Jabu's Belly
