As a child, go to the fishing pond and start fishing like normal. Continue fishing until you get a fish that’s big enough to earn a heart piece. Instead of going to the fishing owner, go into the middle of the pond and, while facing towards the owner in the water, hold Z + R (lock and shield). Don’t let go and swim and run to him. Once you reach him, talk to him without letting go of Z and R. He’ll give you the golden scale instead of a heart piece! This allows you to do many things early on, such as entering Zora’s Domain without having to play Zelda’s Lullaby or getting the heart piece from the Lakeside Laboratory.