I know of the glass idea, but I have also read that putting your live rock in a bucket with a salinity of 1.040 will send every critter in the rock scurrying out of the rock and into the bucket. I have tried this twice now on a few rocks with great success. I have managed to pull out 3 stone crabs, 1 porcelain crab, various copepods etc, serpent starts, hermit crabs and snails. I dont see a downfall to this method besides wasting some salt.