Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Assuming you're talking about the little ball on the coral, it looks like bubble algae to me. Most people consider bubble algae a pest algae, as it tends to spread relatively quickly and not much eats it. So, manually removing any you can see would probably be the recommended course of action (most people would probably recommend removing it in a tub of saltwater outside of the display tank - I don't know that it's necessary, but that's what most people would probably recommend).