No, it doesn't seem like a hole. When it's contracted, the dark spot seems to be the same as the coral tissue. I would pick at it but don't want to cause a problem. I'm new to reefing so have no idea why it's still alive. I bought it, took it home, and THEN researched it to find out it was going to be a problem. I do feed too much, as all newbies do, so it has probably benefitted from my ignorance. I do filter with a HOB which I change at least once a day. I also have a HOB Bak Pak skimmer, which is awfully small but does pull out lots of greenish/black skimmate that I have to clean out daily. I am feeding everybody a blender mix of Sally's Reef Plankton, Mysis Shrimp, Emerald Entrée, and Cyclops. I added some silversides to the blender, as well. Poured the mix onto a cookie sheet, froze it, and broke it into pieces that thaw fairly quickly. Recently, I have been adding Kent's Essential Elements to the water weekly. Everybody, fish and corals, seems happy.