Just to make things more confusing, I have two cases of major TN going on where it stopped just short of killing the entire coral.
This one has looked like this for over a month. If something was eating it, I would think it would have finished it off by now. On the other hand, water conditions or any other stressor would obviously affect the whole coral, not just all but the last 2mm of one branch. The little bit that's alive has actually gotten some color back recently, so I'm somewhat hopeful that it may come back.
This one occurred more recently and was more rapid. The TN started at the base but left this little bit of base alone. I'm not sure what happened - there is a slight possibility the anemone touched it but I don't think so, but it did fall off the rock once and may have landed partly on an Aiptasia.
And sorry Jared, I don't want to put them in a small dish or try to get them under a microscope, because I still hope they might come back and they can't take any more stress.