In lakes and reservoirs the best daytime rotifer netting may be at a depth of several meters. Can You Dig It For sheer numbers of rotifers, dig down and take a sample of wet sand, a few centimeters down, just above the water line. A cubic centimeter of damp sand can hold hundreds of individual rotifers. And while your out and about, remember that moss is a rotifer stronghold. Wring a pinch of moss out in a petri dish and look for rotifers, nematodes, and waterbears.
Dry moss is no problem.
Just sponge up some water and squeeze it out. Out will rain dormant rotifers that in a few minutes will rehydrate and wheel into action. But be careful. You could get hooked and spend your life studying these bizarre little animals. This informative text includes color photomicrographs by Bruce J. Russell.