I just put an emerald crab in in the hopes that it will take care of the very minor, but ever present valonia I have in my tank. I have read a lot of mixed reviews from "they are the greatest thing since sliced bread" to "they ate all my coral" so I am anxious about it. So far, he is eating little bits of algae on the live rock and bypassed any soft coral, so my fingers are crossed. Anyone else have positive or negative experiences with them?