I have a pair of angels(just got them), a pleco and a peacock eel in a tank with sand instead of gravel so vacuuming to clean the bottom is out of the question. I had two botia loaches that I sold last week and now my gravel is getting dirty on top. I'm thinking the loaches were keeping stuff from accumulating on the gravel...by eating it and swishing it around so the filter picked it up. I'm thinking about picking up a couple more botias, but since I didn't have them in with the angels, I am wondering if they are compatible? What about kuhli loaches? They interest me... which would be better for the purpose of helping to keep the sand cleaner- kuhli or botia loaches? Would the angels try to eat the kuhli if I went with them?