Currently fish are all standard quality, meaning that recipes with fish are locked to standard quality as well. My thought is that quality could be tied to the currently mostly invisible size system, assuming that each fish has a maximum and minimum size it can be in the game.
#Fish Quality
lilac lava
young beacon
Agree, we keep track the biggest fish we get of each time but for some reason this serves 0 purpose in game 😭 why we keeping score if it doesn't do anything
crimson furnace
I think quality should be tied to knowledge like for crops. Maybe it needs some balancing, because currently it is very hard to gain fish knowledge compared to crops.