The finder of this species, Horst Linke, describes the habitat rather exactly as follows (I translate his words into English):
“The species lives in Danau Rasau (lake Rasau), a lakeformed widening feeding the great Sungai Batang Hari near Ratanpanjang, about 76 km northeast of Kota Jambi extending till Tanjung and from there in the Sugai Batang Hari about 15 km further until the Danau Rasau at Rantanpanjang is reached (Province Jambi, Sumatra, Indonesia).
It is an extreme blackwater peat lake (…); the pH measured was 4.1, electric conductivity 30 Microsiemens/cm, and temperature (water) 29,3 degrees Celsius. (…) The species lives together with Betta coccina, Trichogaster leeri, Trichogaster trichopterus (only a few), Belontia hasselti and Sphaerichthys osphromenoides (SIM, CHIANG, LINKE & LINKE 2007)”.
The species was correctly identified only once by the original import of Horst himself (of which I received some animals later on and bred them without problems), again a second time by a new import by Linke, and then never again. The scientific name was given not before 2012. All commmercial imports since that first one claiming to be P. gunawani have not been securely identified. There is a commercial interest by exporters and importers of rare fish species to give them interesting “new” names for the sake of selling them in a difficult market. Only once I saw a photo of them that could have been gunawani; but all others were deinitely other forms from Jambi. There are many bintan-like forms in that part of the island. So, it is highly probable that most of the forms sold bearing that name are (mistakenly or frankly) wrongly named.