George Patterson wrote on Tue, 24 Jul 2007:
The people who are left here (myself included) all think they are fairly
knowledgeable, so we don't have a lot to say if nobody else asks
questions.

OK, I'll try a question.

I had a colony of Bird's Nest coral (Pocillopora damicornis):
http://reef.geddis.org/a/Bird's%20Nest%20Coral/
In the last couple of days, I got that so-called "rapid tissue necrosis" (RTN).

A small piece of the coral starts to die off, turning into a uniform brown
jelly, leaving behind a bleached white skeleton. The infection, or whatever
it is, spreads rapidly, killing inches worth in a few hours.

It seems it can be "fixed" by quickly pruning all the infected parts, along
with a buffer of still-healthy coral. Anything that hasn't yet gotten touched
may well survive. It doesn't seem to travel through the water column.

But on the other hand, any piece of the coral that has been touched by an
infected piece, starts dying off within a few hours (and continues to spread).
It does seem species-specific: killed off all of my (connected) bird's nest,
but didn't seem to bother any other nearby corals.

Anyone have advice or suggestions? This happened to a large colony of mine
before, as you can see from the photos at the link above in Sept 2006.
I regrew the colony over the last six months, to larger than it had been
before. But just lost it all in the last couple of days.

Why does this start? Does the colony just get too big, and maybe I don't have
enough water motion to clean away toxins from the center? I once lost a large
plate coral (Montipora capriconis)
http://reef.geddis.org/a/Plate%20Coral/
in much the same way.

One could always just generally suspect "water quality", but I'm not
stressing the tank with my bioload, and everything else is doing great. For
that matter, the colonies that die all look great right before the few days
of encroaching terminal death kill them. (And actually the extremities
continue to look good, until the brown jelly death infection crawls up the
branches to get to the ends and kill them too.)

Very frustating, a year of growth gone in a day or two.

Comments appreciated.

-- Don
__________________________________________________ _____________________________
Don Geddis http://reef.geddis.org/
"I think," said Christopher Robin, "that we ought to eat all our provisions
now, so we won't have so much to carry." -- A. A. Milne