Have used the fish trap method. One lesson learned: My damsels did not like to feed at the top of the water column, so I had to hold the trap about half way down the tank with one hand, but some garlic soaked food in there, and hold the door string with the other hand. Usually would take them about 10 minutes or so to get used to my arm being in the tank, but then the food urge would overcome them. I trapped six out on consecutive days, never took longer than 20 minutes. Though I waited for hours before I figured out about lowering the trap in the water, as I started by attaching it to my center brace. Good luck.