With the import of Hemimyzon nanensis we were once again able to fill a white spot on the map of fishes that have become known in the aquarium with content. At least for us it is a first import. Hemimyzon belongs to the family of hillstream loaches (Balitoridae) and is closely related to the genus Jinshaia. Both genera differ quite well from the other Balitoridae in that in Hemimyzon and Jishaia the pelvic fins are not merge together to form a sucking disc, but are still separate from each other. In Hemimyzon the caudal fin is straight cut off or slightly emarginated, in Jinshaia it is deeply forked.
The particularly interesting thing about H. nanensis is that all other species of the genus originate from China or Taiwan. H. nanensis, on the other hand, is found in the upper reaches of the Chao Phraya basin in northern Thailand. Like all hillstream loaches, H. nanensis loves strong currents and prefers to feed from solid substrate. The animals are very variable in colour and are peaceful among each other. You should not keep them too warm, 16-22°C are ideal. Very important is clear, oxygen-rich, bacteria-poor water, whose composition is otherwise rather secondary. A good lighting is favourable to promote algae growth. Many microorganisms live in the algae film and are used by H. nanensis as food.
Hemimyzon nanensis grows 6-8 cm long. Since these are fish for specialists, we have imported only a few specimens, all of which have already been sold.
Text & photos: Frank Schäfer