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Euphyllia <RTN>, Percula Clown <Aggr. beh.>– 04/10/12
RTN Theorizing 12/24/08 Hi Crew, <Hello Jason. Minh at your service.> It's been a long time since I've had to write you with a problem. That's good! Unfortunately, one of my beautiful and large Birdsnest just underwent rapid tissue necrosis (RTN). It happened frighteningly fast; in less than a day the grapefruit-sized coral went from healthy to half dead! <I'm sorry to hear about your loss.> While my particular cause is unknown (I suspect encroaching mushroom corals, but unsure), I noticed something interesting. The death progressed along the branches of the coral, not simultaneously. In fact, it spread from base to tips (oldest to newest growth). I understand this is a common pattern. In an attempt to save as much as possible, I broke off branches that were still alive and discarded parts that were totally bleached. <Rapid Tissue Necrosis (also known as apoptosis) is a cellular reaction in corals initiated by various stresses such as bacterial infection, temperature, UV radiation, allelopathy, etc. In this particular case, the encroaching mushroom is a very capable culprit.> More interesting: the frags that had some dead tissue still on them proceeded to degrade in the same manner. Those that were comprised only of living tissue appear OK. <If the tissue on a fragment is undergoing apoptosis, it will continue to degrade until the fragment is dead. I would suggest for you to quarantine any remaining healthy fragments in a separate tank to isolate the cellular reaction. This would allow for the highest survival rate of your Seriatopora guttatus while reducing any risk of exposing other healthy SPS corals to this condition.> This is very puzzling. If this condition was caused by a biological or chemical agent attacking the coral flesh, one would expect that it would either be localized (killing a small area) or all over (killing patches at different places on the coral simultaneously). The fact that the progression moves very predictably along the branches implies, at least to me, that it is innate behavior of the organism, not the result of attack. Perhaps it is an evolved survival mechanism; a last-ditch effort to abandon the skeleton and grow anew somewhere else on the reef more amenable to the coral's health. In our tanks, of course, that would not happen thanks to lots of factors, but possibly on the reef? This may explain why the frags without dead patches survive: the signal to eject never reaches them, so they persist. Do you know of any research in this regard? Thoughts? <Although I have seen broadcast reproduction occur in a similar manner, and some rare instances in captivity, the behavior of tissue necrosis appearing in a predictable band pattern indicates a classic case of apoptosis. This cellular reaction could be triggered by allelopathic attack from a neighboring soft coral. Further reading on this subject is available in an excellent article by Eric Borneman, "The Coral Health and Disease Consortium: New Information on Coral Disease." Link: http://www.reefkeeping.com/issues/2002-03/eb/index.php.> Thanks! Happy Holidays! Jason <Likewise to you and yours. Cheers, Minh.> Question For the WWM Team. SPS RTN and Diatom
growth... cause/s? Allowance/s? 6/11/08 Dear WWM Staff,
<Justin> Your website has been a great resource too me and would
like to thank you for your contribution to the hobby through this
website, it is invaluable. <Glad you find it useful> I started in
the hobby one and a half ago with a 12 gallon Nano that was very
successful. Six months into it I did my research and upgraded to a 70
gallon system. My current system setup is as follows: Equipment 50g
Clear for life pentagon corner acrylic tank with a back corner overflow
box. The top front corners are drilled for the two returns, which is
powered buy an in sump Eheim 1260 generating a 10x. I installed a
closed loop by drilled the bottom right hand side of the tank for
intake and the bottom right for the split returns. (see attached
illustration 1). <None of these came through. Must be
attached...> An external Poseidon PS3, generating an estimated 18x
turnover, powers the closed loop creating a circular closed loop flow.
I run a VorTech pump in an opposite position to the closed loop at half
speed in reef crest mode creating turbulence and an additional 35x. I
have a JBJ 1/10th Titanium chiller running in the well ventilated attic
directly above the tank that is powered by an external Poseidon PS1,
generating an estimated 8x turnover, and returns to the main tank. The
lighting is a PFO mini pendant 250 MH running a 14,000K phoenix bulb,
replaced last month. I run a 24' 65W, retro fit SunPaq PC actinic
bulb and a set of two Current USA moon lights. I recently switched from
an ASM G1 skimmer to a Tunze 9010. My sump is a custom built 20 gallon
with a built in 3g refuge where I keep 5 lbs of miracle mud and Chaeto
under a low watt bulb 24/7. <Stop! I would not have the lighting on
continuously here. Chaetomorpha needs a dark phase... I'd arrange
the light to overlap, be on when the main display lighting is cycled
off> The overflow splits into two where 75% of the flow ends up in
the skimmer side of the sump and 25% ends up in the refuge. I run a
PhosBan reactor with Eco-Phos connected to a MaxiJet 400 that pulls
from the skimmer side of the sump and returns to the return side of the
sump. I do not run a heater as the house is maintained at
74º and in combination with the MH I have been very
successful in maintaining a stable temp of 77º. Current
Parameters -- Very stable. Temp 77º Salinity 1.025 pH 8.3
Calcium 450 Alkalinity 10 Magnesium 1350 Nitrates 0 Nitrites 0
Phosphates 0 <Mmm... I'd read a bit re the need for soluble
phosphate... your system, with the reactor, may be too
"clean" for the livestock's good> Ammonia 0
Maintenance Schedule I change 10% weekly using Reef Crystals, but
recently switched to Reefer's Best. <The ZEOvit product> All
sponges are removed from the skimmer, pumps, PhosBan reactors and
cleaned out, to ensure no phosphate built up. I dose B-Ionic and or
DT's new CA/Alk/Mag chemical additives. I dose a little Potassium
(explanation later on) and Eco-Systems trace minerals. I run carbon for
5 days a month. I test all water parameters every Sunday at 8pm using
Salifert test kits. Feeding Schedule I feed sparingly once a day and or
every other day. I feed with Rod's Food (http://www.rodsfood.com/).
Bio Load 1 Med. Yellow Tang 1 Dusky Jaw 1 Blue Chromis 2 small Clown
fish 1 Royal Blue Tang 1 Small Six-line Wrasse 1 Peppermint Shrimp 1
Emerald crab Large cleanup crew (no stars), snails, (Hawaiian Trochus
Grazers, Hawaiian Turbo Grazer, Micro Hermits, Blue hermits, Strombus
Grazers conch, ninja, Pinky Cuke, Hawaiian Littorinid Grazers, Astraea,
Nassarius) Natural Filtration I have about 50 lbs of live rock and
30lbs of live sand. Light Cycle Moonlights off 7am Actinic on 11am MH
on noon MH off 9 pm Actinic off 10 pm Moonlights on 11pm Issues I have
two ongoing issues that I cannot seem to resolve. 1) Diatoms -- (one
year later) 2) SPS RTN/STN <This both may well be due to the
lack/absence of HP04...> I went through a very patient cycle and
waited and waited. However I still to this day suffer from Diatoms. I
have done everything listed on WWM site and more I have done two days
of darkness, however they always return and are very prominent on the
sand bed. They are densest by my Dusky Jaw, as assume it's because
the snails get used in the construction of his burrow and hence they
stay away from him and the sand does not get mixed up in that area,
however the rest of tank still suffers from bad diatom blooms. I can
keep pink and green Birdsnest that grow thick branches and have
wonderful plop extension and color. However, I cannot keep any other
SPS. Monti's die by STN/RTN within weeks and never show signs of
growth. I started adding potassium as the ZEOvit system promotes it and
I had run out of options. I acclimate slowly via the drip method and
place the coral low in the tank and slowly raise up towards the light
as to not light shock the coral. All other forms of corals start to
loose their tissue and then the diatoms start to attach and I
inevitably loose the coral. (See illustration 2) I have recently
increased the weekly water changes to 15% and switched salts from reef
crystals to Reefer's Best to address the low potassium issue as
tested by a ZEOvit user. <K presence/concentration is rarely a rate
limiting factor> Other Info The only piece of equipment that I did
not buy new was the tank and it was used as a freshwater system. My
build thread on sdreefs :
http://www.sdreefs.com/forums/showthread.php?t=25429&highlight=50g+build
Illustration 1 Illustration 2 Illustration 3 <Again, these graphics
didn't make it> Kind regards, -- Justin A. Hai <I'd pull
the Phosban out... run this system for a few weeks... see what happens.
Bob Fenner>
RTN Question -- 5/25/07 Hello and happy Friday, <Hi there and happy Saturday!> I have a couple of questions regarding RTN. Can RTN spread to other corals? <RTN (Rapid Tissue Necrosis) is more a description of the condition than the name of a specific disease, akin to renal failure as opposed to Polycystic Kidney Disease. So could it spread? All depends on the causative agent. More info here and the related links in blue: http://www.wetwebmedia.com/corldisfaqs.htm > I have a pink birds nest coral that grew to the point where one of the branches pushed against the rock it was glued to, and dislodged itself while I was on vacation. <St. Murphy at work again!> I noticed that some of branches tips were starting lose their color so I reattached it, it got worse so I fragged it. <A reasonable move.> The fragged coral seems to still be turning white from the base upwards on all of the frags, then one of my Montipora cap started to discolor in the middle of the cap about a month ago, and has lost some of the tissue in that area, and has spread to the outer rim. <Sounds like zooxanthellae expulsion, perhaps there is an environmental issue at work here.> I have gotten back to changing out 10% of my water/wk and running a magnum 250 with carbon. My water parameters: 150-Gallon Tank Nitrate 0 Phosphate 0 Calcium 400 Alk 10 Temp 77-79 Salinity 1.025 Magnesium 1200 <OK.> Can a build up of salt creep on the top of the tank if dislodged kill corals, or burn them? <Oh, yes.> I've made corrective action to minimize this just in case. <Good.> I have a couple of soft corals Xenia that's uncontrollable <Heeee! Often the case!> 7 different types of Acros that are unaffected A couple Milli's (one showing signs that a small area on one branch might be effected. A couple of Red Monti Cap (both are now dying) <Uh oh!> I feed Nori 1-2 times/day for my powder blue tang, and Foxface . I use Selcon one a week A mixture of frozen Cyclop-eeze, formula 1, formula 2, sweetwater zooplankton, frozen Mysis 2 times/week. Am I missing something that I should be feeding my SPS here? <Seems like a good variety.> I know it's not predatory, and I changed out one of my halide lights because it was over 12 months old. <All sounds good.> Can pruning xenia cause in increase in allelopathy and cause this? <For the most part, Xenia is one of the least toxic corals, but a few species do produce a chemical that is capable of damaging stony corals.> I have to prune this thing every few days or it'll take over all of the lighting at the top of the tank. <Xenia can be invasive.> Thanks for help, <Welcome! Mich> -David Superglue stops RTN! - 01/24/06 Hi all,
I just wanted to say I have seen this work! It has worked
wonders against RTN for the people that i know who have
used it. Just figured it put it out there so more people
would know. Have a good day and happy
reefing....Lucas (you just cover the affected area with it plus
a little of the good tissue around it. stops it completely
and new tissue will grow over it in time.)
<Interesting... to speculate on the action at play here. Bob Fenner,
who is reminded of the "Windex scenes" in "My Big Fat
Greek Wedding"> SPS RTN !!! <?> 8/9/05 Hi Crew, <Ramy> Great site indeed, up-to-date info for sure !! I have purchased an Acropora frag a couple of weeks ago and the base was kind of white, or missing any colouration. <Typical...> After 3 weeks, the size of the white part is still the same, meanwhile, the rest of the frag is very healthy and shows very nice polyp extension. <Good> My question is, is there any chance that this unhealthy part can spread or do you think that it will recover. I have very good lighting, excellent water circulation and all the other corals are doing just fine. Is it true that RTN can spread over a few days and kill the whole piece ? Thank you. <... this whitish area is not likely RTN, but just resultant die-off from the actual fragmentation process... RTN can indeed spread rapidly... I would not worry here. Bob Fenner> RTN issues 5/4/05 Folks @ WWM, howdy.
Recently, I have been experiencing RTN/STN in my tank. It started when
I recently hooked up a chiller and tuned it down too low, shocked a
couple of things. It went down by 6 degrees overnight from 81 to 75 and
probably killed a colony, stressed out 2 other and a bunch of frags
died. Over the next few days, the temp slowly came back, so I thought
everything should be fine and I started to see other corals bleaching
from the base up. This time, I have a salinity problem. I was using a
hydrometer with a faulty arm so all the time while I thought I was
mixing at 1.025 it was actually 1.021, when I tested it with a new
hydrometer <I would really invest in a refractometer if I were in
your shoes. They give you very accurate readings and are worth every
penny.> ...this is a week after the temp got back to normal and over
3 days the specific gravity was back to 1.025. Anyhow, my question is
that does RTN/STN spread and contagious? < I would not say it
is contagious per se.. But if a coral is sitting next to another and
dying, it will release toxins which could cause another to recede. So
in this case heavy water changes and running fresh carbon would really
help get the toxin level down.> Basically most that are affected
start to bleach from the base up and few others have patches of white
here and there, especially one of my caps. I'm very concerned and
don't want this to be an ongoing problem or I will lose the entire
tank. I've lost a couple of things and I can deal with that but I
have lots more coral too precious to lose...Some affected colonies are
permanently attached since they encrusted so they're still in
there. I change 15% water every week and it has good flow, O2, water params are fine now. I hope this can be stopped and
not sure how I can stop it... < I would really get the carbon going
and change that every few days just till things settle down. Also do
the water changes about every 3 days just to be sure things are stable.
And get a refractometer.. Acros are very sensitive to change so it is
important to get that salinity dialed in exact with water changes etc.
The only real way to do that is with a ATC Refractometer. Also is it a
slow recession? RTN in my experience is almost overnight that you will
lose the whole colony. If it is a prize coral that you want to have the
best chance at saving, you can frag a small piece of it from a side
that is the farthest away from the recession. Hopefully the frag will
make it and you will at least have that piece to start a new colony>
Please help!!! Thanks in advance... SJ <Good Luck
EricS>
RTN in SPS frags I have experienced RTN in a few of my small SPS frags. Where does this come from? It seems to just begin upon the tips of the coral's branches. Should I break off the white parts or just see if it cures itself? Any advise you have would be great. Thanks!! <wow... this is a question that literally cannot be answered in less than pages. RTN is not clearly defined or explained. It is a term applied to several if not many conditions in coral (some pathogenic, some not... rather stress/heat related). Do peruse the WWM archives and beyond for current discussions on this topic. Most of the popular reef authors have written on this topic. Eric Borneman in Reef Corals book is most thorough and current. I discuss it as well in my book on coral propagation. I cannot say much without so much more information (what you call RTN: is it necrotic and rotting tissue or bleaching/expelling zooxanthellae... how old is the coral... did you quarantine it... so much more...?). You best bet is isolation in a QT tank, heavy aeration, ozone would be ideal... but use iodine if no ozone is available. You may also use an antibiotic in the hospital tank as well or in a strong extended bath. Best regards, Anthony> SPS RTN Event? <<<Anthony Calfo with the follow
up>>> Tank Specs: 120G ETS Skimmer 2x175W MH with 2x65W PC ph
8.2 - 8.35, SG 1.025, nitrate 20, calcium 400. <Everything listed
seems pretty good. Your nitrates are a little high, but your clam
(listed below) will enjoy/consume that. I would like to see you keep
track of your alkalinity and temperature.> << Temperature is
maintained by a Medusa temperature controller at 80. I have not check
alkalinity in awhile - I'm depending on the ESV supplement to keep
it in range.>> <<<wow... blind faith. Charming, but not
at all safe or recommended <wink>. A fine product but the
manufacturer's rec. doses are merely guidelines. You must test and
dose accordingly. X teaspoons per X gallons means nothing in a system
with 500 clams or 1 clam for that matter. It is the daily demand for
Ca/ALK that should determine how much supplement is added>>> I
add ESV calcium/alk supplement every other day, iodine every week and
coral vital every now and then. I've been moving my tank over from
a FO to a reef over the last six months or so. I've replaced the
bioballs in the wet-dry and added a bunch of live rock. I've
upgraded the lighting as well. I currently have a large Naso tang, a
large derasa clam, a couple of cleaner shrimp, misc snails and hermits.
A couple of weeks ago I went and picked up a mushroom rock, a zoanthid
polyp rock and a SPS - a Montipora. I put the SPS high up on the reef
in a place where the return pump created some current. The SPS looked
good for two week showing clear signs of growth. Overnight this piece
of coral "melted" away. When I got up in the morning about
75% of the coral was gone. <There is an important distinction to be
made here. Has the tissue disappeared or has the tissue remain but lost
its color?> << The tissue is gone. I have removed the skeleton
at this point. >> I did a FW dip (hey, what the hell) knowing it
would probably not help. It's been several days now and the coral
looks stark white. Any chance of the coral making a recovery? <Again
it depends if there is still tissue left.> Is/was this a bacterial
problem? <Hard to say at this point.> Any suggestion to how I can
prevent/decrease the chances of this happening again? Thanks! <I
will refer you to an excellent article by Julian Sprung. It is titled
"Coral Bleaching" and it is in the Marine Fish and Reef 2002
Annual magazine. This is a once a year special issue magazine put out
by the people who publish Aquarium Fish. See if you cannot find it at
your LFS. Hopefully, it will help you diagnose the exact cause for your
loss. -Steven Pro> <<<yes... agreed. So many reasons for
Coral Bleaching (light/salinity and especially temperature shock
<sudden increase of 4 or more degrees), pathogens, weak Ca or Alk
levels, etc.>. There just is not enough information to make a fair
diagnosis at this point. Best regards, Anthony>>> Is This RTN [Rapid Tissue Necrosis]? BOB, <<JasonC here filling while Bob is away diving.>> Need some help having my first encounter with some kind of disease that is attacking one of my SPS corals. One of the lower branches of a tri color coral has lost all of its pigment and has died over night. I have placed the infected coral in its own tank with hopes that the others don't get infected. <<quite wise to isolate it, in case this is a pathogen. RTN isn't really a disease, it's more like a description of conditions - there's going to be something else going on - need to look further.>> The coral that was effected looks like the skin has just vanished with just small traces left on the dead branch. twelve hours have passed and the rest of the colony does not seem to be effected. <<ahh good.>> Any advice how long i should leave it in quarantine? <<perhaps as long as is practical - a month perhaps, two weeks if you can't stand it and it's continuing to do well. Again, if this is a pathogen, you will need time to identify it and treat appropriately.>> Should i do any thing to the main tank? <<run all the normal tests, keep watch in the spot where the coral was placed - in case there is a new predator you didn't know you had, nearby sweeper tentacles, etc.>> should i try to salvage some frags off the unaffected part of the infected colony? <<You could, but if this is a systemic problem with the coral, the resulting frags will take the problem with them.>> Is there a cure or should i let it take its course? <<with the exception of stepping up the observations, wait.>> temp and lighting have been consistent and the effected branch was on the lower part of the colony. <<How low is low? Some/Many of the SPS corals do this to their lower branches as the top branches grow into the nutrient-rich stream/currents.>> It's been 36 hours and the bleaching has not progressed. Am I in the clear, or should I wait longer what do you think? <<I'm a big fan of patience, and because these are all closed systems, you really don't want to introduce [although it may be too late] pathogens. It's a good thing you have the quarantine nearby so you might as well use it for as long as seems useful. Is a difficult question to answer as there's just not a ton of information about the various causes/problems/cures for sick corals - mostly anecdotal, personal accounts. Stay patient, and in the meanwhile you can read through the SPS FAQ's: http://www.wetwebmedia.com/stonyfaq.htm >> thanks Kurt Keener <<You are welcome - I hope it helps. Cheers, J -- >> RTN Good morning Bob. Have been doing some reading on "RTN". Do you know if there is any on going research on RTN and if they have found exactly what causes it and any new cures or treatment for this ? <Plenty o' speculation... fungus/es of sorts being carried by the wind... overheated reefs... a combo. of influences...> I have been trying to find some article or on this subject. A lot of the books that I have read don't really say what causes other than maybe stress or changing there environment. <Take a read through "The Modern Coral Reef" books by Fossa and Nilsen, and Eric Borneman's latest (great) tome "Aquarium Corals"... this is an "old complaint" that many thought we were done with (at least in the trade). There is a bunch on this in the scientific literature... I have a piece on how to search this on the WWM site. Bob Fenner> Like more hobbyists I have lost some nice SPS colonies to RTN. Have a great day. Barry |
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