Despite the latin name (cruciatus = torture or torment), these seem to be peaceful towards their own kind and other species, at least in the confines of the stock tanks at work.
Admittedly, they were a little problematic shortly after arrival, and after receiving confirmation from the supplier that they were from very soft waters, we moved them from one of our normal systems (run on our local hard, alkaline tap water) over to our softwater system which is pH 6.8, general hardness 4 degrees. Since then, all perked up and appear in great condition.
Here are some pics from the photo tank, the loaches turn a golden colour when presented with a black substrate. They are 1" TL:
And some more 'natural looking' shots from the stock tank. When at ease, these fish search the substrate at a 45 degree angle:
Emma
I have that problem myself 