Lol if you have two Colossoma macropomum then you will need a much bigger tank,
you may get away with keeping two in a 55G for a few months, but you will need around a 200g to house them properly.
No chance really. They can grow too big for a 100G in one year. For life you are looking at a heated pond or an aquarium 12ft long by 5ft wide.
They really are huge.
ok when i was in 4th grade i bought 4 fish includeing 1 pacu i went back next week and got 1 pacu and 1 more fish two of 3 of them were tinfoil barbs 1 was some kind of shark/catfish it died in a month later i got 3 gold gouramis they all got eaten then for christmas i get a 55 and we set it up and move the fish 1 of the tinfoils died before we moved them and then the other one did now 12 months later the last tinfoil barb dies and i still have 2 pacus one 7in the Other 5in
It's possible that the Pacu's have become stunted then. I cant be sure though because I havn't seen them, so I could be wrong. However I'm led to believe they are stunted because that is very little growth for a Pacu in that space of time.
Also a little bit worried about the amont of deaths you've been having with your fish. They should last for many years. Possible bad stock?
I think Pacus, among a few others (paddle fish, Giant Gourami, alligator gar), shouldn't be sold in stores unless special ordered. Most of the time they're just doomed.