My emeralds are awesome, too. I've got 3-- one that's huge (about 3") and two newer little ones. They all chow down on bubble algae. I may have to get another one or two though if those darn bubbles don't go away... Oh, and I've got a clam, and they've never gone anywhere close to it. They do eat algae off corals though, but I've not seen them actually damage any coral.