in lake hylia - ocarina of time - there are two pieces of heart you can get from the laboratory. one is on top of the roof and up the ladder.
the other you can get by diving really far down while inside the building. but first you have to get the golden scales by catching the largest fish in the fishing pond. you can only get the largest fish by becoming an adult and completing the water temple. once you have the golden scales you can dive deep enough for the old freaky man to give you a piece of heart.
Lake Hylia lern the serinade of water and play it you will appear in lake Hylia
lake hylia
You have to take the cannon by paying 50~100 rupees.
There are four feet from the Great bridge Hylia to the lake in Twilight Princes. This is made into a game.
Get the silver scale in Zora's Domain, then go to Lake Hylia through the warp door. The letter is near the door at the Lake Hylia end.
warp
You have to go to the bottom of lake Hylia.
you must save the zora boy. his dead mother will then give you a new piece of clothing to wear. it will allow you to breath underwater.
After you beat the Water Temple, then the lake fills up due to the rain. But first you need the Hookshot, metal boots, and the bow. The hammer helps as well.
you get it in the temple at the bottom of lake hylia
Do the Zora diving game. Win it. The you will get the Silver Scale that allows you to dive deeper. It allows you to dive for 6 seconds. That will allow you enough time to dove to the bottom of Lake Hylia to get the bottle.
Use Minda to warp the giant lava rock from Death Mountain to the frozen part of the lake.