Finding a Reekfish is a necessary part of the game that allows players to journey to Yeto’s Mansion.
After acquiring Ashei’s sketch, a closer look reveals a strange creature holding a red fish. By acquiring the scent of the fish, Link may be able to track down the creature in the sketch. Taking the sketch to any Prince Ralis in Zora’s domain will reveal the the fish in question is the Reekfish, and the Prince himself will then give Link a pair of Coral Earring’s to use as bait.
The Reekfish feed on the coral located here.
In order to catch the Reekfish, players must fish near Mother-and-Child Rock, located in Zora’s Domain across from the entrance of Snowpeak. The rocks themselves are located next to each other, one larger than the other. This is the only place the Reekfish can be found in the game.
Fish at Mother-and-Child Rock, and use the Corral Earring’s as bait. After catching the Reekfish, transform into Wolf Link to record the scent of the fish and continue on your adventure.