I've heard they can be mean, but I got one at saltycritter, when he was small, about the size of quarter, and he's fine in my tank with a mandarin, two dottybacks, niger trigger, yellow tang, pink spot goby, flame angel, and the other assorted critters. Occasionally, he'll pick up a snail or hermit and then just drop them. I think he copied this off of the trigger. Size wise he about 2 inches now and seems to have stopped there, but I've seen them 5 inches long. My tank size is a 120. Anyway, take the info for what its worth...