Thanks for the positive comments.
The fishtank is over two years old now and I have had no issue about anything apart that the fish once had white spot. All fish are happy and I hope it will stay as it is.
Basic tank setup is shown on the picture. There are two water pumps, an Eheim Aquaball Powerhead 650 l/h and an Eden pump 300 l/h. The Aquaball Powerhead takes water from an undergravel filter and the Eden is located at the other side of the spray bar so both pumps together make a 'Run' habitat which I prefer over 'Riffle' habitat. The fishtank is 3 foot long.
Temperature is set to 24 ºC. The water temperature in Borneo is typically a few degrees (2 - 3) cooler than air temperature so I think it is ok. At least the fish are doing well.
All Gastromyzon coming over to NZ under the name of G. borenensis but we have a very slim chance to see true G. borenensis. What species I have seen so far are all Gastromyzon which are collected at Sarawak and Kalimantan around Kuching town. I wish I am wrong, but if I am not it does mean that we can't see more then 10 species here in NZ, even less than that, out of 35 Gastromyzon species.
If anybody would like a hillstream fishtank, don't rush out to a LFS to buy all these species. Just be patient and over time you might see different Borneo suckers in your shop.