I put a large net in the tank for a few days and started putting food in the net at each feeding. It got comfortable enough to swim in the net to get the food, when she did, I pressed it against the glass to make sure she was in then scooped her out. I actually caught both the tang and trigger together. I used this method to catch my red coris wrasse as well, only took half a day to catch that one
no stress, no chasing, just patience.