Zora Scale

Zora Scales are fragments of the skins of Zoras. They seem to hold the aquatic identity of the Zoras, as a non-Zora in the possession of one finds themselves better adapted to water.

Ocarina of Time
Ocarina of Time features both the Silver Scale and the Golden Scale. While the Silver Scale is stated to be a Zora Scale, the Golden Scale is not and can only be assumed to be one based on its many similarities to the Silver Scale.

Silver Scale
Link's own abilities allow him to swim downwards for no more than three seconds, or in distance, three meters. When he reaches Zora's Domain, he can participate in a diving game. If the young hero collects all of the blue Rupees underwater before time runs out, he will be rewarded with the Silver Scale, which appropriately enhances Link's diving capabilities to up to 6 meters.

Golden Scale
The Golden Scale is an enhanced version of the Silver Scale. The time and depth of a dive that can be achieved with the Golden Scale is up to nine meters. Unlike obtaining the Silver Scale, gaining the Golden Scale is optional, although it is necessary to obtain a Piece of Heart in the Lakeside Laboratory. To obtain the Golden Scale, Link must catch a fish that breaks the current record by at least 4 pounds at the Fishing Pond in Lake Hylia during the future years. That is, if the record to beat is 9 pounds as Adult Link, the young hero only needs to catch a 13 pounder to obtain the Scale; if the record is 11 pounds, then a 15 pound fish is necessary to receive the award. Once the Golden Scale has been obtained, the Sinking Lure will become available to find at the Fishing Pond as Adult Link.

While previously unconfirmed, it is stated in Ocarina of Time 3D that it is indeed a Zora scale.

Oracle of Ages
In Oracle of Ages, the Zora Scale is given to Link by a Zora after Link defeats Plasmarine and gets the Rolling Sea from Jabu-Jabu's Belly. The Zora Scale is required to bypass the Zora guarding the way to the Sea of Storms. On the Sea of Storms, Link will find the stranded Piratians. The Zora Scale, which is a charm capable of calming the seas, is given to the Captain of the Piratians, so that they can escape the Sea of Storms. As thanks, Link receives the Tokay Eyeball, which is required to access the Ancient Tomb.

Twilight Princess
In Twilight Princess, the Zora Armor is made of Zora scales. It was created by King Zora himself for the destined Hero. Interestingly, the Zora Armor makes its wearer vulnerable to fire and ice, weaknesses Majora's Mask's Zora Mask established to belong to the Zora race.

Phantom Hourglass
In Phantom Hourglass, the Zora Scales are among the treasures that can be sold on Mercay Island to the Teller of Treasures for a fixed, random amount of Rupees. It is also a highly valued commodity among members of the Ho Ho Tribe.