whats the question? Are you asking what the maroon stuff is? It could be 2 different things... If there are bubbles in it, it's cyano bacteria and there is very little you can do other than a water change and cut back on feeding. It really doesn't look like that though, it looks more like a maroon coraline algae, which is a nice thing. If, on the other hand, you mean the star fish, it may be eating your coraline