here r some pic of my 2 different piranha they where in tank and now i have sifted to the pond with my pacu .because i thought that large space will change the color .and they r improving....
I highly doubt it. Between the adult rbp, pacu & the strong filtration that's gonna be needed for 2K gallon tank, any rbp fry will have like .0001% chance for survival. Pacu will end up suking the eggs up before the even hatch. & they might spawn if you have both sexes & the fish are comfortable.