There is another soda bottle trap you can make that I have used for damsels and caught about 12 in 1 hour period. I didn't feed my fish for a day so the trap would work a little better.

I took a good sized plastic bottle, cut it across about 1/3 down from the lid, took the top piece and turned it upside down and stuck it inside the bottom piece. Put a piece of frozen food inside the trap and once the damsels swim inside to get some food, they have a hard time finding the small opening to get back out and you have enough time to pull the trap and fish out. I'm horrible at explaining things, you might be able to find pictures online if that made no sense.