My dad was a heavy line fisherman seldom was he ever caught with a fish larger than his line weight, my grandfather was the opposite he often fished with 2# or 4# leaders. But, in both cases a lot depended on the type of fish and the circumstances.
I enjoy the fight and playing the fish. Pacu is a robust fish and so far I have yet to have one thats been released die.
I use a slow 9' rod and an ultralite Okuma spinning reel.