Persona 5 How To Unlock Fishing & Catch The Guardian?

Read a book called ‘Fishpond Spotter’. This will unlock the fish pond. You can also accept a invitation given by Ryuji during certain point in the game which unlocks the fish pond.
_______________________________________________

Catching the Guardian of the Pond:
_____________

You have to buy the book called ‘Essence of Fishing’ which can be bough from Shinjuku. This book makes it easier for you to see fish using your third eye and where the fishing line needs to land in order to catch them. You will need around 400 points to purchase Top-class Boilie is what the Guardian like to eat. O & The Guardian in third eye is the Golden 1.