Go to the nearest Sell NPC or Merchant
Open the sell menu
Select the fish you want to sell
Use the Sell All option if available
Confirm the sale
Repeat at another selling location if your inventory is full or the NPC is unavailable
Go to the nearest Sell NPC or Merchant
Open the sell menu
Select the fish you want to sell
Use the Sell All option if available
Confirm the sale
Repeat at another selling location if your inventory is full or the NPC is unavailable