Kuhli loaches also have a low bio load for their length, so you can have several of them without worrying too much about how they will impact the tank's biology. In fact, since the kuhli loach is sort of a social fish, you should always have four or five to keep them happy.
I should note that I don't have the best tank bottom for kuhli loaches. While I have plenty of places for them to hide, my gravel is much larger than they would like. Kuhli loaces do better in fine gravel or sand.