Zora's Fountain
Ignore the big fish (Jabu-Jabu) for now and instead swim behind him to
the southern part of Zora's Fountain to a small island with a tree, some
bushes, and two boulders. Put a bomb next to the gray boulder to blow a
hole in the wall and get the Farore's Wind spell from a great fairy. Now
swim onto the platform by Jabu-Jabu's mouth and walk up to him. Use the
bottle with the fish in it to offer the fish to Jabu-Jabu, thereby
making him open his mouth and swallow you.
