Bartian, I could not reply earlier. The male fish in photo 2836 is without any doubt a P. sumatranus. Even the small filament in the end of the caudal is well to be seen.
The other fish in the next picture is – I am afraid – definitely no sumatranus. I cannot say which species it is; it resembles a bit a poorly coloured anjunganensis, but it maybe quite a different form, even a hintherto unknown. I suppose, it’s a male too.
It is very rare that shops mix different species. They probably haven’t done this in the Netherlands but they will have received the fish in a mixed bag. This is rare, too, but it happens. You should try to get some sumatranus-females, too. P. sumatranus is one of the most interesting species we know, since it is coloured in the bintan-like manner, but displays head-up similar to ornaticauda. Sometimes, it will even stand still more upright, really in an angle of 90% (defiitely vertical)!
It would be of great importance to build-up a new stock. Several years ago, Karen Koomans from Nieuwe Pekela ha a big stock, but all are lost in the meantime.