my star polyps always look black with little to no green on them after i frag them or they shut for a few days. they color back up in a day or tow.
i had a rock covered in gsp, i really needed to get rid of them so i took the rock aout and was cutting big chunks off with a knife and razor blade. i then scrubed a bunch of it off with a tooth brush. that was like 4 or 5 days ago, i thought i got all of them off, but now theres a bunch popping up where i guess i missed some tissue. it sux because i wanted them all gone, but it gives you an idea of how hardy these guys are.