detailed information you can get in the above mentioned article (although it is in German).
We found Neurergus derjugini in small and medium sized streams in 1200 to 1400 meter a.s.l. Water temperature 13- 14 degree Celsius , Carbonat hardness above 20
The habitat is similar to that of the other stream type Neurergus species N. strauchii and N. crocatus.
The currently valid concept of the Genus Neurergus was created by Schmidtler and Schmidtler. The key factor in the designation of the species Neurergus microspilotus was the assumption, that Neurergus derjugini was a synonym of Neurergus crocatus. This was based not on personal experience but on the statements of older researcher for instance Wolltersdorf. Schmidtler made this confinement explicitely.
But as mentioned above, N. derjugini is definitively different from N. crocatus and very much more closely related to Neurergus microspilotus.
But you may think this is bean counting, it is very interesting.
Habitat of N. derjugini one animal left in the foreground