I agree with man, in Amazon River you can find Arapaima gigas (Pirarucu), they can reach 440lb, heaviest fish in Amazon River, you also can find PiraĆba, the heaviest catfish in Amazon River (about 300 lb).
Unfortunately I'm not going to Amazon, but you can find Red Tail Catfish in another places in Brazil, not as big as in Amazon. Where I live right now I can find Red Tail Catfish from 22lb to 80 lb.
I was thinking in a Penn Battle 2 6000.
What u guys think?