I am in the process of setting up my tank; with only water, rock and sand added so far. Today my wife send me a pic of a critter she saw in the tank. Up til today we have only seen one small snale, and then this... I know the picture is blurry, best she could do with her tablet... Is this a mini-brittle starfish? If it is, are these good to keep as cleaners? Or should I get him out of there?