Location and Uses
When worn, the Zora Tunic eliminates the need for Link to breath underwater; thereby, most of its use is seen while wearing the Iron Boots. The tunic is immensely useful while exploring the Water Temple and in the completion of several sidequests. However, it is a completely optional item and is not strictly needed to complete the game, as all underwater objectives are able to be completed in the time before Link's health expires. Similarly to the Goron Tunic, the Zora Tunic can only be worn while Link is an adult.
There are two methods of obtaining the Zora Tunic, the primary one being by using Blue Fire to melt the red ice in which King Zora is encased. The king will bequeath the tunic to Link as a reward for saving him. The only other means of procuring a tunic is by purchasing one from the Zora Shop for the cost of 300 Rupees.