When you obtain 20 shock arrows you must then use them to disable the giant elephant thing that is shooting the water in the Zora Domain aka Vah Ruta. During the fight he will shoot a bunch of ice blocks at you which can do quite a bit of damage and be difficult to evade. How do you destroy the ice blocks during the Vat Ruta battle?
If you look closely at the blocks that he fires at you, you will see that they are the same blocks that your ice rune uses. If you switch over to the ice rune and enable it, you will be able to shatter these ice blocks using this rune and in turn, be able to evade all of the ice attacks that Vah Ruta uses, very easily.
Toward the final stage of the battle, you will need destroy cubes and mines. The mines always come from behind and the cubes always come from the front. Just a handy thing to know as it can get a bit crazy before you hit the final red orb to disable Vah Ruta.