I had a damsel that I ended up catching in a ziploc bag. Had even tried fishing for him before trying the ziploc (smallest hooks i had and salmon eggs, no luck). put a large ziploc in tank, rocks to weight it down, and food in it. Did this a few times and damsel charged in, blockd his exit with net. Recently caught a yellow tang with an open plastic jar. put jar in tank, fed only in jar for three or so days, tang started eating in jar, blocked exit with a net. Good luck!