I've got about 70% of the fish found in the game. At some point you get an email from one of the characters that says a great place to find rare fish is a subterranean lake near where he lives.
I've taken that to be the puddle/waterfall at the bottom of the ravine between the city ruins and the commercial center, at the end away from the elevator. However while I've caught a number of things there, they have been extremely common fish (killfish) and junk (RPG).
Am I in the right spot, or is there another location for rare fish? Is there anyway to increase the chances of getting rare fish?
I am playing on PS4 so answers which would require a mod to the game will not work.
Update: So the ravine just outside the commercial center which I'm asking about above is NOT Emil's home, which is what is referenced in Emil's email. Just to be clear, and that's why I wasn't finding some of the rare fish.