FIshing in this game is a total ♥♥♥♥, and I'm here to try to help you guys through it

First, you're going to want to START FISHING, by pressing the 'action button'

you want to select the area to start fishing, by moving around witht the arrow keys,
once you release the action button, you will cast the line.

After your lure sinks, moving it around is really... confusing

to me it seemed if I hit 'left' it went right, so try to figure it out

you may have to wait for a fish to bite the line after a couple tries, (yes they do let go sometimes)

when luring in (i will get to that) you dont want to lure in from the side, there seems to be a glitch when that happens.

(sorry for lack of photos)

Fishing, here we go

When a fish/frog bites the line it will say something like "HIT" or something, but you will see it clearly

to lure fast it seems you have to use the jump button
to lure a littlle slowly use the 'action' button

make sure you lure the line closer to the center of the edge you are fishing from, by using the arrow keys

im afraid this is all I can help with, I hope this was helpfull