how about taking a fish net, put some mysis or cyclopeeze into the net (really fine net for brine) and hang it about a half inch below the waterline. damsels are smart, and after picking at the bottom for a while they will get the hint to go up to the top of the net. then, after an almost sore arm, you can bring them out of the water. it takes them a while to get used to the net. good luck!!!