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FAQs about Merulinid Corals Disease

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Coral eating itself??? 3/10/11
Hello Crew!
<Hey Mark>
I seem to be having a very odd problem with the health of one of my Coral.
My Hydnophora appears to be eating itself.
<I see this>
It seems to have started earlier today when I noted that the corner of the colony was starting to deteriorate.
At first I thought it might be Tissue Necrosis or some bacterial disease, but after a few hours of observation it looks more like neighboring polyps are eating each other.
<Mmm, don't think so>
Those polyps have their guts/filaments thrown out over the other nearby polyps, and in their wake they leave ravaged flesh of their own colony.
I read up as much as I could on common coral diseases but I can't find anything that even seems to hint as to what's going on here.
Attached a picture with this message of the affected area(and no the coral is not bleached, my camera and reef tank lighting just don't get along)
Like I said, I am really at a loss here as I initially suspected necrosis, but I have never seen anything like this before or referenced to.
Kindest Regards
Mark
<The reddish area near the mal-affected portion of the Hydnophora is my prime suspect... Perhaps Cyanobacterial... If it were mine and not too hard to do, I'd move this stony coral colony to another "less red" area in this or another system. Bob Fenner>

Re: Coral eating itself??? 3/10/11
Hey Bob, thanks for your reply.
<Welcome Mark>
I really didn't even consider Cyanobacterial as a possible cause because I assumed it was coralline as it did not look slimy or come off when squirting at it with a baster, nor is any of it in actual contact with the colony, but it could also possibly explain what's happened next.
<Ah yes... the Monerans we grossly group together as BGA are of many different colours, physical types... A small scrape and look under a 'scope will quickly ascertain which Division, whether this is a Thallophyte or no>
I felt I could not wait for a reply so I got out the hacksaw and fragged the affected area.
<Mmm, another approach!>
There has been no new degradation since, and the fragment I removed which I decided to try and salvage and moved to another part of the tank has also stopped degrading.
So far things are looking normal again, but I will update you if anything new happens.
Kindest Regards
Mark
<And you, BobF>

Re: Coral eating itself??? 3/30/11
Hello again!
<Mark>
Looks like my troubles with this colony still isn't over.
I has soon been almost 3 weeks since we last communicated and I'm afraid my Hydnophora colony still is not doing very well.
What is more, small patches on the main colony still seem to vanish in a similar manner to that which prompted this original message exchange, though I have not observed anything that could be eating the colony, day or night.
The colony still has its normal color but refuses to open at all.
However the rest of my reef is perfectly healthy, from Shrooms and Zoanthids, Hammers and Brains to Monti's and Birds Nests.
<... the first three are very toxic... esp. towards "newcomers". Did we discuss allelopathy last time? Did you read on WWM re acclimating new Cnidarian life to established systems?>
Even an increased frequency of water changes and carbon replacement has not done anything for it.
<And won't>
And I have kept the rock that the colony is encrusted on free of any trace of cyanobacteria.
Frankly, I am at a loss of as what to do about this slow deterioration and refusal to open, and the only thing out of the ordinary is that a few days before my problems started I re-aquascaped, but that's all and I did not add any new livestock or rock to the tank.
Hope you can figure out what may be going on so I can nurse this guy back to health.
Kindest Regards
Mark
<Read here: http://wetwebmedia.com/cnidcompppt.htm
and the Compatibility FAQs for Corallimorpharians, Zoanthideans, the genus Euphyllia/family Caryophylliidae on WWM. BobF>

Hydnophora health decline. Env. and allelopathy 6/21/07 Hello guys, how's things? I'd like some help here, I'm having a Hydnophora that seems to be dying <dying> there are a number of factors this could be attributed to so i would like help in narrowing it down. The problem started a few weeks ago, my Hydnophora simply just refused to inflate, i <I> was also having problems with summer temperatures, it was abnormally hot and tank temperatures were fluctuating with up to 6 degrees <Yikes! Too much> over 24 hours, down to 78-79 and peaking at about 84, i managed to get that under control with a fan. Then i also noticed that one of the surface powerheads had quit and a thick scum layer on the surface formed, i did note some of my Palythoa loose some color. <Both trouble> after a week or two of not inflating it finally browned out, and now i am seeing bare skeleton in the brown areas which suggest to me a tissue necrosis of sorts. I also have a briareum colony in the tank, <...> possibly and possibly not toxic <More likely so> (frequent water changes and carbon usage), my candy cane and Favites brain who are both very very close to it seem unaffected (just a few inches away, measured between expanded polyps). with all these problem thou the other colonies have remained healthy including my Montipora that's growing like a weed, i did however note my Zoa frag being closed up alot <No such word> of this period but seems to now open up again after i cleared the surface scum. I have checked the water parameters, nitrate, calcium, PH, hardness etc. and they all check out fine. Short summary of the symptoms, deflated, brown out, tissue recession. so the big question, what's killing my Hydnophora, the stress from the temperature swings under control now) surface scum blocking out the light? now under control) or allelopathy even thou its farther away from the briareum colony than most of the other corals? and what can i do to save it? Hope to hear from any of you soon, Best regards, Mark Forsling <Is highly likely the variable environment, the encrusting Gorgonian and Zoanthid at play here. Solutions? More water changes, carbon filtration, moving/enlarging their world... Bob Fenner>

Coral Recession... Merulina - 08/05/07 Hi, <Hi Brian, Mich with you again.> You helped me identify this a few weeks ago and it had been doing fine. Now I am noticing some recession. <I am not surprised. This coral is not generally not easily kept in captivity. Merulina often suffer from tissue recession, bleaching, decalcification and overall failure to thrive and the causes are seldom well understood.> Any ideas? <Tissues may be compromised by sediments and contact with other corals> What can I do to slow, stop it? <Is difficult to say, as the causes are not often able to be determined. You will need to keep sediment off of this coral. Keeping your water quality as high as possible with frequent water changes and regular carbon replacement may help. Borneman recommends generally leaving this coral alone and untouched. He further recommends keeping this coral under strong lighting and a good distance from any potential allelopathic organisms. Merulina grow quite slowly so if, and a big if here, it does recover it will likely take a good bit of time. I'm sorry, I wish I had better news for you.> See attached pic. <Got it. Thanks, Mich>

Coral Recession... Merulina - 08/05/07 <Hello again Brian, Mich here.> Guess I deserve it for not doing my research before I purchased. <We are all human and hopefully we learn and grow from our mistakes.> Need to practice what I preach. <Yes, don't we all?> Actually we need a mobile solution to be able to look something up at a LFS in the case we see something we like that we do not know what it is. Here's an idea for a new web site. <<RMF has seen some shops making Net access avail... where folks can easily "look up" at least what there is to find thus>> You email a picture of a coral and it emails back info about it. Just need a coral identifier system :). <Heehee! Actually Jake Adams is working on a mobile coral reference guide that can be down loaded to your MP3 player. See his website here: http://www.coralidea.com I hope you find this helpful. Mich>

Hydnophora Dying -- 09/08/07 I wondered if you could help me with my Hydnophora frag which has been doing well i my tank for half a year now, recently i have been seeing major tissue recession from the main body, and exposure of the skeleton, its gradually got worse and worse and i don't know what to do i wondered if you can be of any help at all. All my parameters of course are fine, <Hmm... what does "fine" mean exactly? These corals need your water chemistry to be as close to natural sea water as you can get it. (i.e. salinity 1.025-1.027sg, calcium 410 to 420ppm, alkalinity 3 to 4 mEq/L, etc. Always keep in mind that what's "fine" for one coral might not be so fine for another. You'd be surprised what I can get some species of Zoanthids and clove coral to grow in. But Hydnophora is a bit more picky.> recently lost a Ricordea which may have caused this what do you think? <I doubt it, unless maybe if the tank is really small.> The Ricordea did start to disintegrate due to too high water flow causing it to be moved around. <It might not be disintegrating. It might have just scrunched up and let go to find a better spot.> please help it looks so gorgeous and i understand they are not the easiest of corals to keep but that is why i took up the challenge, but my hopes have been dashed by this recent event and i am at a loose end. I hope the picture helps you with your diagnosis. <These corals often suffer frightening tissue recession before getting truly settled into a tank. But they're also known to make some heroic recoveries. Do you feed it anything? If not, that's likely part of the problem. Keep it under strong light and moderate water flow and start target feeding it. If you have to, turn the pumps off for an hour or so while feeding.> Yours Laurence Sykes <Good luck, Sara M.>

Hydnophora Dying 9/10/07 I wondered if you could help me with my Hydnophora frag <Forgive me if I already answered this email. I can't seem to find my response anywhere so I'm afraid maybe I never sent it. Anyway, here it goes again...> which has been doing well i my tank for half a year now, recently i have been seeing major tissue recession from the main body, and exposure of the skeleton, its gradually got worse and worse and i don't know what to do i wondered if you can be of any help at all. <This is typical for Hydnophora which is not yet settled into a tank.> All my parameters of course are fine, <Hmm... what is "fine" exactly? What's fine for one coral might not be fine for another. Hydnophora need water parameters as close to natural seawater as possible (calcium 410 to 420ppm, salinity 1.025 to 1.027, etc.)> recently lost a Ricordea which may have caused this what do you think? <Highly unlikely unless the tank is really small.> The Ricordea did start to disintegrate due to too high water flow causing it to be moved around. <It might not be disintegrating. It likely scrunched up and let go to try to find a better spot.> please help it looks so gorgeous and i understand they are not the easiest of corals to keep but that is why i took up the challenge, but my hopes have been dashed by this recent event and i am at a loose end. <It's quite common for these corals to suffer frightening tissue recession when not well established in a new tank. Fortunately, they're also capable of heroic recoveries. Do you feed it? If not, that might be part of the problem. Try target feeding it (turn off the pumps for an hour or so if you have to).> I hope the picture helps you with your diagnosis. <not doomed yet... could definitely come back with some TLC> Yours <Good luck,
Sara M.>

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