Beautiful fish and shot.
I agree with you on the ID of a true filamentosum despite all the opposition from other peers, who adamantly say Peru piraiba are the false piraiba aka capapretum. This is so prevalent down here in Florida that Rodrigo of Predatory Fins is forced to sell tankfulls of Peru piraiba as capapretum for $65, because he is told by peers and his buyers that Peru piraiba doesn't exceed 3' for many years in captivity, or maybe ever, but true piraiba (and they mean here in part the Suriname piraiba) reach 4'-5' in 5 years in captivity and keep growing.
The growth rate disparity is true in our 1sthand experience as we have two 5 yo Peru stuck at 2.5'-3' and one 4.5'-5', 6yo Suriname that keeps growing... but from all my knowledge capapretum look distinctly different, especially when younger, babies and young juvies. Yours above I'd ID as true filamentosum in my present knowledge, of indeed Peru variety.
