BORNEO HILLSTREAM LOACH (Pseudogastromyzon myersi) 2403

Mostly restricted to shallow, fast-flowing, highly-oxygenated headwaters/minor tributaries characterised by stretches of riffles and runs broken up by pools or cascades in some cases. Substrates are normally composed of smaller rocks, sand and gravel with jumbles of boulders, and while riparian/stream-side vegetation and patches of submerged leaf litter are common features aquatic plants aren’t usually present. Information regarding sympatric species is lacking but it certainly occurs alongside Liniparhomaloptera disparis, Schistura fasciolata and Rhinogobius duospilus on a frequent basis.

The most favourable habitats contain clear, oxygen-saturated water which, allied with the sun, supports the development of a rich biofilm carpeting submerged surfaces. Hong Kong and Guangzhou have a humid, subtropical, monsoon-influenced climate, and during periods of high rainfall some streams may be temporarily turbid due to suspended material dislodged by increased (sometimes torrential) flow rate and water depth. In Hong Kong at least the water is often slightly acidic, nutrient poor and of low conductivity (Yang and Dudgeon, 2010).

https://www.seriouslyfish.com/species/gastromyzon-viriosus/