There has been a spate of kidnappings, especially of Arkasodara, so you decide to follow Matsya to his village to keep him safe.
This quest is available if you have completed the quest A Fisherman's Friend.
Starting the Quest
Talk to Estinien in Thavnair to begin the quest.
Search the Area for Matsya
Go west to the quest icon in the minimap. You may wish to speak to the Chocobokeep along the way. Then check on the sparkling Destination to proceed.
Search the Area Again
Go north so that you can go northwest up the slope to where the orange arrow is pointing in the minimap. Check on the sparkling Destination to proceed.
Search for Matsya
Go north to the orange circle in the minimap. Enter the glowing purple circle and defeat the three Tempered Imperials that appear.
Render Aid to Matsya
Check on Matsya to proceed. There will be a cutscene.
Optional: Thavnair Aether Current 1
On the way to the next quest icon, you may wish to attune to the Aether Current. It is east of the quest icon.
Speak with Matsya
Go to the quest icon and talk to Matsya.
Go south from Matsya and talk to Khanga, then go southeast from Khanga and talk to Hasveydah.
Speak with Matsya Again
Go north to the quest icon in the minimap and talk to Matsya to complete the quest. There will be a cutscene.
Next Main Scenario Quest
After you complete the quest, talk to Matsya to accept the next quest: The Great Work.