Fishing Hole Passes are quest items from The Legend of Zelda: Majora's Mask. They exclusively appear in the Nintendo 3DS remake of the game. These passes can be obtained as a prize at Honey & Darling's Shop, the Deku Scrub Playground, Swordsman's School's Expert Course, or given by Madame Aroma at Milk Bar on Final Day. They can be redeemed at the Swamp or Ocean Fishing Holes for one free Fishing Rod rental, as opposed to paying the regular fee of 50 Rupees for one fishing session.
Fishing Hole Passes are given away as rewards for completing tasks which would result in rewards of various amounts of Rupees in the original Nintendo 64 version of the game, such as the completion of mini-games or Side Quests. However, they are usually only given out as a reward after Link has already received a different reward for completing a task for the very first time.
Since that are quest items, Link will retain any and all Fishing Hole Pass after resetting the 3 day cycle with the Song of Time.