The Catch was launched a year back in the game, and I was among a pool of players who completed the grind really fast. Not to show off, but the paucity of time made me go to extreme measures. I remember messaging some friends to let me fish in their world, and the only tip I can give you is to co-op with other people and ask for their permission. There were times when I was in other worlds and requested permission to fish. Sometimes they allowed it, whereas other times, they wanted to fish for themselves. No harsh feelings there, but better to utilize the power of networking here. If you don't have enough friends, then you should take it slow and wait for the cooldown to reset for fish spawning. There are plenty of spots in the game, and slowly you can gather all the required fish.