Secret Treasure under the Great Fish is one of the Side Quests you’ll discover in the Lanayru Great Spring region. Side Quests are quests in The Legend
List of Side Quests and Side Adventures - The Legend of Zelda: Tears of the Kingdom Guide - IGN
North Hyrule Field - The Legend of Zelda: Tears of the Kingdom Guide - IGN
The Legend of Zelda: Tears of the Kingdom Guide - IGN
Clues to the Sky - The Legend of Zelda: Tears of the Kingdom Guide - IGN
Secret Treasure Under the Great Fish - Tears of the Kingdom
Tears Of The Kingdom - Secret Treasure Under The Great Fish Guide
Tears of the Kingdom - How to Find Secret Treasure under the Great Fish - Gamepur
Walkthrough - The Legend of Zelda: Tears of the Kingdom Guide - IGN
Zelda: Tears of the Kingdom - Secret Treasure Under the Great Fish Walkthrough
Secret Treasure Under the Great Fish - The Legend of Zelda: Tears of the Kingdom Guide - IGN
Zelda: Tears of the Kingdom (TotK) — Secret Treasure Under the Great Fish Quest Guide – GameSkinny
Misko's Treasure locations in Zelda: Tears of the Kingdom - Polygon