Bill, you mention photos of JJphotos.dk that seem to show P. deissneri; at least they were named like this.
I just tried to find that photo, but without success. But that portfolio is huge, and the pictures are of many authors, not by the owner of the site himself. The main point that I want to make is the follwing, however: The true P. deissneri is – in the male sex, but we generally distinguish the Paro species by the males in courtship colours – easily to be recognized, and normally in this species there is no reason for errors (see the pictures of male deissneri at our homepage).The very special form of the tail fin including a black filament and the very special colouring of the unpaired fins by separated short streaks instead of a continuous coloured band is highly specific. There are few websites only that are aware of this and illustrate fish named deissneri by photos of real deissneri. I should be interested to see that picture of which you say that it seems rightly to show that species. I doubt that. If it did it must be really specific and could be named without any doubt.
Generally I encourage you as Helene and Russ did to try the fish offered by that shop but obviously named wrongly. Despite of the name, all species and hitherto undescribed additional forms are beautiful fish; in some cases we could name them rightly but not in all. In fact, most of the Paros offered by the trade are no-name Paros because they were caught on Sumatra where some places are left that promise the professional catches a good harvest. Rarely, the trade offers fish from Western Malaysia or Kalimantan (Borneo), never from Sarawak or Bangka. And most of those fish from Sumatra are not scientifically described up to now; so, there is no “right” name presently. P. spec. Sentang or P. spec. “blue line” are the most frequently sold Paros in the zoo trade, but they bear provisional names only. And often even these fish are not identical; the fish offered bearing these provisional names have sometimes been collected at different sites, for the catchers and the exporters have no interest and experience in the fine differences of local variants. Nevertheless: they are beautiful fish. And its entirely unimportant whether they are “true species” or what sort of variant to an already named species “only”. There is a certian risk of different variants having been mixed up, but the risk of different species having been mixed like this is very small indeed.