I cant see your pests very well, but if they look like these white guys in my picture, they are Tunicates. It is a type of Sea Squirt and are not harmful. I have them on this plug of my Goni and a couple have spread to the back of my tank. Mine have been growing for a few months and I have left them alone for now.Can anyone tell me what this pest is, and if it is a threat to my reef. It’s a very small white/ or translucent oval shaped pest. I’m seeing them on my glass as well as coral and live rock.