my 2 cents to the bottle trap--first, don't feed the day before you put the trap in. Second, before you put the trap in, punch a hole in the bottle near the cut end, so that you can quickly pull on the string to pull the bottle (in a mouth-up position) out of the tank as quickly as possible if you see the fish swim in. I just put a small weight on the "dry" end of the string so it would just hang outside the tank and I did not need to stand there holding it. I got a pesky pseudochromis out of the tank this way. I will admit it took several sessions of watching and some patience.