To be honest when I first saw the pics of yours on your other thread I thought, they aren't Nandus nandus...
But now im just totally confused, yours look very similar to my suspected Polycentrus schomburgkii but yours are somewhat more elongate.
There are no real good sources I have found to help identify them, most pics available even on fishbase and the like are not exactly definitive. I have been looking through the databases at university trying to find some good information but nothing as of yet.
My fish are still pretty small, so probably have a lot of changing to do, maybe I should wait before I try to ID them...
Actually do your Nandus have extended rays at the front of the pelvic fins. Both my P.abbreviata and P.schomburgkii have extensions on the first ray of their their pelvics but from the pic it doesn't look like yours does...
I've searched around too with no good luck. My suspected "Nandus" is around an inch and a half right now. It hasn't grown that much over the months. I agree on the pelvic fins. Mine seems to have no extension. I'm not home right now to confirm this, but I doubt he has any.
they look exactly like my nandus nandus, just a different pattern to the body, all fins and ray extentions are almost identical.
very nice fish, i have had my nandus pair for nearly a year and have hardly grown! must just be slow growers as they eat loads!