Volker, allani could clearly be excluded (you said it yourself by comparing that picture of G. Kopic. But one has to say: this picture does not show the typicial allani; this big round spot is not to be seen in most individuals). P. allani is the only safe species occuring in Sarawak, and we had never commercial imports from there. Anyhow, allani was never commercially traded before at all. Once it will be the first, of course. But surely not this time.
But it could be sumatranus. This species is very hard to be photographed. The picture you show to us (by I. Koslowski) is the most colourful we have, and that is not typical. Most male sumatranus are much less colourful, sometimes even looking nearly black and white. There is a faint reddish tone in the caudal and sometimes clear reddish lines in the dorsal and anal, but rarely this overall reddish tinge of that photo.
P. sumatranus is a very strange species. It can have a slim body just similar to parvulus and ornaticauda, but in other populations it can have a higher body just similar to the “normal” Paros. Especially strange is the fact that in courtship the male displays head-up; I try to find an old photo of Karen Koomans. She bred the species with 5 pairs tigether in a tank of about 60 liters, and it looked like “a group of soldiers on parade”.
Additionally, there have been commercial imports of sumatranus several times; the last in Germany was about two years ago. The names are always wrong, of course.
So I conclude that your fish might well be this species, and I strongly advise you and your friends to buy some of them in order to breed them. As I said, in breeding they exhibit their full behaviour (and colours, I should add). But the main reason is: Our overall stock in the project is very small indeed. The danger of loosing them again is very high. If the species determination could be confirmed, you and your friends should have a try to enlarge our stock by offspring! To breed P. sumatranus is not as difficult as ornaticauda or some others and very rewarding.