This is something of a bit of debate ... I have them and when I see them I pull them out ... They have eatin most all of my coraline algea .... and in a nano this can happen quick as anything ... Soooo I lean against them.. There is also some question that they may much on corals ....however I have not witnessed them doing that just cruising over them and irritating them for the most part . There most distructive behaviour IME is eating coraline .
