I had 2 Bifa's, both females, and I was surprised how big they got. Like 12 inches in a little under 2 years. Rio Chacamax from CoA. I'd think the males would get huge.
I have a WC Black Belt, and it hasn't gotten up to 10 inches yet, I think mine's a runt.
I have a Syn and a Melanurum, they grow really fast, they're around 12 inches now.
I have Zonatus, those get thick, long, high-bodied, BIG fish. And they eat a lot, too--at least twice what all my other Vieja eat.
Argentea grow so slow, I couldn't tell you how big they get--just that they take forever to get however big they're gonna get. Regani same thing. I've kept both species for 3 years now, and I don't have a truly adult fish, yet.
I kept some red head Fenestratus for a couple years and they got real big real fast. Easy to confuse with Hartwegi, too. If you have a 14" Hartwegi, you might want to throw his pic up here and let everybody see--might be a Fenestratus. I'd heard Hartwegi only get about 10 inches? Not sure about that, though.