This answer was posted by the Zelda Master.

Well, Jabu Jabu (as you may know) is a giant crocodile. To get to him, follo these
instructions.

1. Enter Zoras Domain.

2. Head right to the top, where the king is sitting.

3. Go into the tunnel (left) and play the diving game.

4. Win the diving game, then head back up to the top.

5. go into the tunnel and claim your prize.

6. Dive down into the water. There should be a doorway under the water somewhere. Swim to
it (underwater) and go through.

7. Float up. Look around the lake, there should be a bottle in the water. Dive under and
pick it up.

8. Read the mesage inside, then return to the big fat guy at the top of Zoras Domain.

9. Talk to him, tell him about his daughter. He will then move over and reveal the way to
JabuJabu! Please rate this, and remember, I will attempt to answer ALL questions (read the
hint i posted)

The Zeda Master.

When you get to Jabu Jabu, use the bottle to catch a fish, then place the fish in frount
of Jabu Jabu.

Then you are in the Young Link water temple...

thank u