A couple different sites say the quality of the fish don't matter, just quantity. You need 300 points at the end of the day to get the trophy, and each fish is 1 point for the first 3 and 2 points for fish after that in each round.
After some rough calculations, I'm guessing IF you had 2 good rods, 200 pieces of bait, and 17k bells in your inventory, you could get it done in 2-2.5 hours. Of course it would take half the day just to get that much bait... If only there was batch crafting.