Acropora help?

[Anemone]

Well, it's not classical RTN - the "R" stands for rapid, and you'd generally lose the whole colony in a few hours.

You may have a different bacterial or stress induced necrotic event. Unfortunately, this isn't really up my alley, so hopefully someone else may come along and give you some tips. If it were me, I'd frag some 1" pieces as far away from the affected area as I could.

Kevin

 

[DJ Lobster]

I acquired a new piece of Acropora sp. a week ago. A couple days ago, I noticed a largish piece of the skin was missing, but it was deep down between branches in the colony, so I assumed that maybe it escaped my notice and was like that when I bought it from the LFS, as a result of insufficient light or current. But every day after I first noticed the missing tissue, it seems to be loosing more everyday. The coral is not bleaching, it's almost as if the tissue seems to be peeling off- I can see the ends up it hanging a millimeter or so up off the skeleton. No algae has grown on the skeleton yet, but amphipods swarm on it at night.

System is a 25 gallon tall tank, 6-8 DSB composed mainly of Southdown and 2-5% larger grained sand, 15 lb of live rock. 2 PH, no skimmer, 4x65w PC lights (2 6500k and 2 Actinic), no skimmer. I do a weekly water change of about 2.5 gallons, in which time I skim the top of the tank. I add Kalkwasser nightly, but do not dose any other elements, or use carbon. Temperature remains steady at 80o, and I do not test for pH or anything else- I judge from the tank's inhanbitants how well things are going for the most part.

Is this RTN? Should I buy iodine and dip the coral? Frag the untouched branches? Maybe the work of underfed amphipods (though I seriously doubt it, and assume they're only drawn to the already dying tissue)? I have directed a PH to send a little more current to it, and it's pretty high up in the tank, mayb 5" from the lights. Any ideas?

 

[Ben1]

I agree it isnt RTN but probably what people generally call STN. It is bacterial and most likey IMO is caused by lack of good current. IMO this is the problem with wild SPS heads. As they grow in the wild they come very dependant on the current in their location. They grow in a pattern meant for this current. For example pollicipora colonys grow thinner branching colonys when taken from higher current situations. It is impossible in many cases to duplicate these wild currents in are systems, which is why captive frags thrive better.

FWIW I had a colony with STN, although I was suggested to frag it, dip it ect. I moved it to a higher current area. The tissue grew back and coral is doing excellent now. It is a wise idea to make atleast one frag far from the infection though. In my 75 SPS system I am running 3 large powerheads on a red sea wave maker and a 3/4" sea swirl at 750 gph. I still think I could boost the current and get better results.

HTH

 

[Minh Nguyen]

Is this a wild colony? If it is, you will probably will not able to save it. It is not RTN because RTN will be over in 1 or at the most 2 days.
I would move it to a higher flow area. If this does not stop, I would frag the colony and throw away the center. Make sure none of your frags touch the dead part, even if you have to leave a 1 cm margin from the dead coral area.
Good luck.

 

[Sue Truett]

DJ, is there any polyp extension in the peeling areas?? I don't think it is RTN either, but maybe what Eric Borneman describes as SDR. Shutdown response. The coral just stops thriving for whatever reasons. In this case I think the lighting may be a problemas acropora, wild at that, need intense lighting to acclimate to captive systems. Current is also on the light side for a wild colony of acropora. Like Ben said these wild colonies have to have trememdous amounts of current to even try to acclimate to captive systems. I don't think I'd try to glue over the peeling areas as they sound kind of large and this may end up covering the whole coral. I would try to keep the coral as high in the light as possible, good alternating current, and do some water tests to make sure the alk./ca. are where they ned to be. In small systems it doesn't take long for things to get out of hand. Good luck.

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[witchdoctor]

You should also make certain that it is not the target of chemical attack from a neighboring coral. Many soft and LPS corals exude chemical defenses that can destroy surrounding corals, especially if they are downstream.

 

[Mike106]

Another possibility is to super glue over the dying area and some a portion of the living tissue around the infected area to stop the spreading. Then move to the higher current areas.

good luck.