P. spec. aqua-tropica05/11

It’s P. spec. Sentang from Sumatra. This has been the worldwide most traded form in the past years. Often it is called P. spec. bintan, for it is certainly closely related (if not identical) with P. bintan.
Therefore we can say: The Parosphromenus in aquaria that are most widely distributed do not clearly belong to one of the eighteen species scientifically hintherto described, but to two of the hitherto undescribed forms, namely “spec. “blue line” and spec. Sentang. It’s ridiculuous, isn’t it? But it’s the truth, because the great majority of licorice gouramis in the aquarium are not self-caught fish or fish stemming as offspring from such fish with a definitely know place where they were caught, but from trade. And the forms that are traded mostly are the both I mentioned.

(I removed the picture formerly at this place because it is not necessary for answering the question of Hendrik’s. But it is interesting in itself for all: Therefore I show it at a better place: in the picture’s section).

What is the difference to bintan?

If I knew I would tell you. Nobody knows exactly. Both forms are obviously closely related. They even maybe genetically identical. But we have no information on that so far.

P. bintan is a scientifically described species with a known sources of discovery. It was described by Kottelat in 1998 and two islands were given as source ot its natural distribution: Bintan and Bangka. So, Sumatra does not belong to that list, or better: It is not mentioned in the scientifical description. The spec. Sentang has first appeared named “sintangensis” in trade without a clear mention of a source in 2006 or 2007.The latinizied name sounded similar to a scientific description, but that was a fake by the trader; perhaps he was himself unclear about that or he thought of better deals. Nobody knows. Anyhow, the name was changed to spec. from Sentang (Sumatra), and it was clearer what the source was: an unknown place near the Sumatranian town of Sentang. That means: We must separate both, because it is wholly unclear what the exact relation of the two amounts to.

But: Anybody who knows both forms sees clearly the close relation. The spec. Sentang is identical with bintan or it is a close relative. If it is identical, then the list of the natural sources of bintan given in the scientific description of Kottelat’s is incomplete (this is well possible, I should say: it is highly probable). If it is not identical, it most certainly is at least closely related.

The case cannot be solved before we have genetic data. Presently we must separate the two and say, that spec. Sentang is a bintan-like form stemming from Sumatra, and it is to be distinguished by a slight differention in the colouring of the male: it is slightly less markedly coloured, with often a little greenish tinge in the fins. It should not be kept together with bintan in one tank, for it is – to say the least – definitely stemming from a differnet place far away from Bintan and Bangka, therefore at least a local variant of bintan but possibly even a different species. It is probable however that both forms could be crossed, but we may not have any interest in mixing the forms until we don’t know of their status. We should not produce mingles of different species if we have no knowledge on this matter.

Christian, if it were as you argue, then there should be no more spec. Sentang in trade. But if I see it correctly, there are.
We have first to explain the masses of spec. Sentang that have been traded during the last years. Why so many? This form was the most-traded Parosphromenus in 2009, 2010 and 2011. An explanation maybe that all water bodies around in that region were “free for full exploitation”, maybe the vegetation was destroyed first and the catches became quite easy. This happens sometimes in Europe when there is a big building project and all fish or amphibia one could get on are fished or caught before the destruction is completed. But in this case the trading went on (or goes on?) for years. Therefore we have also to explain if this form is still in trade today. To me, it seems so. But how is that possible if all the habitats are destroyed already?

You are right, Christian, nobody confirms that. We detect no serious differences, the fish are sold with the same name, so we think they come from the same source. Yes, that must not be the case. Nevertheless, it is probable that even if most former habitats in the Sentang-area are destroyed in the meantime, some ditches or other waters are still existant. The fish of today may not come exactly from the same source, but they might come from nearby sources, that is: from the same place (if “place” is taken in a generous sense).
We shall see: I feel reminded at the “blue line – hype” some years ago. There were “blue lines” everywhere in Europe to be found in the fish-shops, and then, suddenly, it was (nearly) out. This time, it is likely to go the same way.