littlesilvermax said:
Do you know for sure?
I am so sad.
I'm 99% sure. There might be one spot on that piece containing a little tissue, but it looks like it RTN'd to me. Especially if it happened over one day's time. Rapid Tissue Neucrosis is visibly indicated when a section bleaches white (like yours) and travels quickly across the rest of the coral. If you ever see a coral start to bleach in one area, you might consider pulling it out immediately, cutting off the bleached area <b>and</b> a half inch of healthy tissue to stop RTN in its tracks. Another way you can determine if it is RTN is when the whole piece bleaches but no algae has grown on it at all.
One more thing to watch for. If you happen to see your SPS piece with some type of milky mucous floating off of it, that is how RTN occurs. Healthy tissue is literally sloughing off the coral, and a turkey baster can blow it off, but you'll see more tissue going with it.
SPS are beautiful, but can be mysterious they way they suddenly just give up even though everything seems fine. Sure, we can overheat the tank, or overdose the water with kalkwasser accidentally, but what is really aggravating is when all is perfect, and the coral (the one you just noticed the day before has really been doing great) suddenly dies.
As you can see, I've had a little experience with this. I grew a small birdsnest frag (a veritable twig, so small I couldn't believe I was gluing to a rock in the first place) grew into a lovely golf ball shape. I had just commented how nicely it grew and how it was hard to believe it came from that dot of tissue so long ago, and the next day it was white/dead.
It is just that the poyps do not come out anymore, even at 4 am.
