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FAQs about Zoanthid Social Disease  (Allelopathy)

FAQs on Zoanthid Disease: Zoanthid Health, Pests, Predator 1, Zoanthid Health, Pests Predators 2, Zoanthid Health, Pests, Predators 3, Zoanthid Hlth., Pests, Pred.s 4, Zoanthid Hlth., Pests, Pred.s 5, Zoanthid Hlth., Pests, Pred.s 6, Zoanthid Hlth., Pests, Pred.s 7,
FAQs on Zoanthid Disease by Category: DiagnosisEnvironmental,
(Pollution/Poisoning, Lighting...), Nutritional, Trauma, Pathogenic (Infectious, Parasitic, Viral) Predatory/Pest, Treatments 
& Zoanthid Reproduction/Propagation,

Related Articles: Zoanthids, Sea Mat: An Ocean Of Color For The Aquarium by Blane Perun,

Related FAQs: Zoanthids, Zoanthids 2Zoanthids 3Zoanthid ID, Zoanthid Behavior, Zoanthid Compatibility, Zoanthid Selection, Zoanthid System, Zoanthid Lighting, Zoanthid Feeding, Zoanthid Reproduction

All Cnidarians need to be slowly, methodically "introduced" to each other... New colonies isolated... when assured of health, absence of pests... water exchanged back/forth for a few weeks.

Ongoing Palythoa problems       12/10/19
Good morning crew,
<Good morning Nicole>
I have been scouring your site and I am sure my answer is there somewhere but I just can't seem to find it.
To keep a long story short every few weeks for many years I will lose a small patch (20-25 heads of thousands) of Palys to this brown jelly type stuff.
<These appear to be some type of sponge >
It will go away for a bit and then rear it's ugly head up again.
I am wondering if there is any one specific thing that causes this condition, or could it be any number of factors and this is simply how Palys react to something they don't like.
Of course I am hoping you can tell me that only one thing could be causing this but I feel like most things in this hobby it won't be that simple.
Thank you in advance.
<Sponges live in almost all marine ecosystems, from the shallowest coral reefs to the deepest, coldest parts of the ocean so, it is very easy that they have adapted to your marine tank; they are filter feeders, not coral eaters, but looks that they are suffocating your Zoas. I suggest to manually remove them; if the rock (s) they are attached to, is (are) easy to take out of the tank, you can remove them with a pair of tweezers or applying hydrogen peroxide directly to the sponges.>
PS while I have your attention, any advice for getting a dart fish out of a deep narrow overflow chamber? ��
<This happens at times and the best solution is to drain the overflow section and try to introduce a narrow net attached to a pvc pipe or some other long object in order to reach and catch the fish in only a few centimeters of water, if access to the overflow is limited, you can try the same but with the net attached to a flexible pipe or hose. Hope this helps. Cheers. Wil.>

Re: Ongoing Palythoa problems       12/10/19
Thank you for the reply.
Yes I do know about the sponges, they don't really concern me.
I am referring to my Palys turning brown and gooey and disintegrating.
<Ahh, ok... I thought you said this happens when sponges are present.>
Maybe the photo isn't very clear. This has been going on long before the sponges were present and often in colonies where there are no/very little sponges.
Any idea what is causing my Palys to turn brown and gooey?
<May have to do with water chemistry / quality>
It will only happen to a small patch at a time, go away, only to return again on a different patch of Palys.
I have attached 2 more photos that will hopefully show what is going on more clearly.
<Thanks, I can see what you mean more clearly on your excellent pix. Can you please tell me about your water levels (numbers)?>
Thanks again and wish me luck catching the dart fish! ��
<Good luck!... hopefully you take him out soon. Wil.>

Re: Ongoing Palythoa problems       12/10/19
Thanks again. The dart fish actually ended up being super easy to catch; for lack of anywhere to hide he swam straight into my net. Him and his 3 buddies were just added to the display tank yesterday.
<Ahh... good, perhaps you can block or limit the overflow slits a bit so that this won’t happen again, slender fish like your dart fish can easily pass through them.>
So back to the Paly problem, I have only recently started testing/dosing after 6 years in the hobby and have attached photos of my logs.
<Okay, let’s see>
My salinity is always at 1.026. I really don't see it being parameters though as this has been going on forever and only seems to affect a very small portion of Palys at a time.
<I don’t see readings re HPO4 and Nitrate... do you dose iodine?>
I know I have some allelopathy issues in the tank due to an unusual mix of corals I introduced before I knew what allelopathy was, so this is my suspicion.
<You may be right here>
I still find it odd that it only affects tiny patches of Palys at a time though.
<Is there any other Cnidarian life in the tank? Maybe nearby the Palythoa colony?>
I was just hoping maybe there was only one possible cause for Palys turning brown and gooey but I guess that is not the case.
Thanks again for your help
<Welcome. Wil.>
Re: Ongoing Palythoa problems       12/10/19

He jumped over the overflow, no way he would fit through the slits. Luckily the tank itself is pretty well covered.
I don't have a phosphate test kit yet, I started testing nitrates in the last few days, you will notice nitrite/nitrate readings on the last few logs on the far right.
<You're right, I missed this.>
Nitrites are always 0, nitrates have been hovering around 5-10ppm although I am not a big fan of my seachem test kit (hard to read)
and plan to get a new brand soon. All other tests are Salifert.
<I use Salifert mostly... a very reliable, easy to read test kit brand.>
I do not dose iodine, I will look into this.
<Iodine is required by most corals but should be dose with caution.>
As I said I am very new to the whole testing/dosing thing, I have always relied on visual observation and frequent water changes in the past, have had a lot of luck both good and bad haha so have decided recently to step up my game and force myself to understand the chemistry behind my aquarium.
<Good decision>
There are lots of corals in the tank, many of which I know don't mix well.
Ricordea, green hairy mushrooms, a few leathers including Colts/devils hand/ pink cabbage, a hammer coral, many Rock flower anemones etc.
But honestly Palys are the most prevalent thing in the tank, mostly due to a very invasive pale bluish green type that is sometimes the kind melting, sometimes not. I have added some activated carbon recently and plan to add more soon,
<Don't forget to suspend activated carbon use when dosing>
but I also know I need to rethink some of my coral selection but I'm not totally sure which to keep and which to move yet!
By the way I don't think I mentioned, this is a heavily stocked 150 gallon tank with a 30 or 40 gallon sump. It started as a 75 gallon 6 years ago and I upgraded to 150 about a year ago.
<Do bear in mind that corals need enough space to open freely without touching the other corals. Cheers. Wil.>

Weird Zoa Behaviour
Hello WWM !
<Hey Francesco!>
Is very long time that i read your website, i mostly often found either what i was searching, either something that was very interesting and useful for my hobbyist knowledge.
This time i need advise...
I am Francesco, proud owner of a pico and a nano, 10 years experienced reefer that just since last September re-started some reefing after a life-changing event (no details needed here :) )
So, on September 2018 i re-started with a 8gal (im a metric man, however i think for the site reference is better to use imperial qtys) Fluval shrimp tank 12"x12"x12", converted... i was eager to re-start, but i had not enough space available for something bigger and however i considered my knowledge and past experience enough to start consciously a nano/pico ( a very small one let's say...)
The tank was setup with a Kessil A80, A Sera PS130 Skimmer (oh the little jewel...) and a HOB filter loaded with ceramics bio media, and a Tunze Turbelle 6040 with controller (oh the beast !)
Inside is now left a 7.7 lb of LR, after an excessive initial load (22lb) that was strongly limiting the water circulation.
Over the months (and especially in February) the system was "converted" with an external "reactor" Sera Prefix, moved by a Newa 1.200 (317 gph :D )
which returns with several spray bars in the cube, creating a soft but consistent multi flow.
Daily, a Jebao OW-10 (oh the little funny thing) kicks 4 times x 30min just to move a bit the water in a chaotic way.
Parameters :
KH : 11.0 - 11.5
CA : 430 - 450
MG : 1350 - 1380
PH : i do not remember last time i checked...
Temp: 24-25
Sal : 1025
Life Stock is
Lysmata Amboinensis ,1 Debelius, 1 Little Ocellaris, 1 Clibanarius tric. Several Zoanthus colonies (4 kinds), 1 hitchhiker green neon Paly, 1 yellow Parazoanthus, a hitchhiker Discosoma (i would say a neglectus ...), Pachyclavularia, a hitchhiker Gorgonia (no photosyn) and a Stylophora bicolor.
Everything is thriving (NO3 1-2 ppm, PO4 0.1 ppm), spreading, coloring, reacting, multiplying... the Gorgonia is now branching from the original little single branch (which i consider a personal success... for the moment...)
All but a little colony of Zoanthus (the last i have put into)
<This is likely an important fact>

that in the last 2 months reduced from 6/7 polyps to 2.
The colony was (and still is) on the frag plate, and was quite arrogantly (from me) positioned in the middle of another giant spreading Zoanthus colony (with some space ... 1" around).
<Mmm; not enough: Insufficient for chemical allelopathy>
While aware that could have been some "chem war", i witnessed many times a self assessment of the fighting parties (mostly softies) and also consider it a necessity for the creation of the coral palette on the LR, so i decided to put them there and observe.
The polyps started to die, one by one, showing the distress signs (irritated polyp, closed mostly of the day or just half opened for few very minutes) one by one, never together.
This behaviour, follow by the progressive shrinking and detachment of the polyp, led me to the conclusion that the disease was parasitic.
<? Really? Did you observe actual parasites?>
I continued so to observe the sick polyps trying to catch snails, Nudis, spiders, eggs, holes, excrements and whatever else anomalous, day and night... but nothing.
Just once i removed an Asterina that was clearly eating one polyp, but i always had the suspicion that was an opportunistic behaviour from the star and not a predatory one.
However the star was removed.
The polyps continued to recede and die.
Two weeks ago i so decided to move the Zoas, and being the "little" tank quite overcrowded, i moved them to the "big".
Very fast : the "big" is a 20 gal tank with 3 movement pumps and a return (200gph) granting a very good diverse flow, has some kind of sump system (my project, quite long to explain, but the functionality is a sump functionality), Sera PS 130 Skimmer (oh i damn love Sera skimmers...) and the parameters are a mirror of the "little".
The tank is equipped with a Kessil 360 which runs at 80% peak (30% blue) 10hrs/dd.
The "big" has started on 07 December 2018, is a quite younger tank but however had a good cycle and just recently got the first load of softies (1 Ric, 1 Rhoda, 2 Discosoma, 3 Zoanthus, 1 Clavularia) all of them "ultra" (as i would like to have finest specimen there, only) and has the classic (for me) Amboinensis + debelius set, and an Ecsenius bicolor that was called in for the algae/GHA initial war as well with 4 Clibanarius tric. and 3 Trochus.
I placed the "sick" Zoa in a very open place, with no neighbours, good light and good movement. Probably i placed them in the best spot of the tank that i was reserving for the (very) future SPS i wanted to try there... but hey... my Zoas are sick !
The behaviour of the sick polyp seemed initially to persevere, with a huge anxiety from my side due to the possibility of having introduced a parasite in the "big" (who is yelling since the start of my email "QUARANTINE TAAAAAAANK!!!!" ??? :D)... however is now a couple of days that the polyp
does not close anymore, however now both of them are stretching up with half closed mouth (also the mouth is stretching to the light), the foot has a length that i never seen in a Zoas... almost 1" ...
So... what is going on by your opinion ? I would exclude a light problem as mostly they now receive a bit more of light, PAR wise... water parameters are ok, and under direct feed (reef powder food from ocean nutrition 2xweek), they positively react...
I do not see an immediate threat and generally i never act on the rush if a catastrophe is not already ongoing, but i exhausted all my possible explanations and i do not feel comfortable so...
While waiting for your reply, and apologizing for the long (and still incomplete) email, i express my whole admiration for the WWM knowledge shared base, the crew and the thousands of times that directly or indirectly you provided help to some reefer pal in trouble...
Thanks and My Best Regards
<My best guess is that the continuing odd/stressful behavior was a continuation of the allelopathy from the smaller system. I would leave the one odd-acting Zoanthid colony where it is for now; and not worry re possible pathogen involvement. I might step up your dosing of iodide-ate here.
Please do write back in a few weeks time regarding your further observations. Bob Fenner>
Re: Weird Zoas Behaviour     3/12/19

Hi Bob and thanks for the super quick reply, will do as advised and let you know !
All the best !
<Thank you Francesco. BobF>

Mushrooms and Zoanthids... allelopathy, starvation knocked on, reading and great self-discovery!   10/10/13
I have hard and soft coral systems that range from Acros to polyps and everything in between. My levels are acceptable if not near perfect for all of my tanks.

The tanks in question are a 75g drilled with 30 g sump. 80
watt led lighting, PhosGuard in a reactor,
<... you realize chemo- photo-synthetic life requires measurable soluble HPO4>

carbon in a bag a week out of the month, SeaChem matrix, refugium, two 750 gph powerheads, 1250 gph
Ammonia, nitrite, nitrate 0
<... sigh: and measurable NO3. Please read on WWM re>

 phosphate less than .25, alk11, ph 8.22
daytime, I feed a mix of flakes heavily, bribe
<Brine likely; Artemia>
 shrimp once a week, phyto once a week.
<See WWM re this as well. Of little use in most settings>

Dose AquaVitro ions, calcification, 8.4, fuel once a week to where Mag stays around 1300, calcium 420, iodine at .06, iron not registering with my red sea test kit, but fuel has iron, so not sure if the test does not pick up this particular type of iron or what. Potassium at 385. This tank houses only soft corals and a tube anemone
<Cerianthus? Not compatible... see WWM re this as well>

 along with fish and inverts. The problem I am having is with mushrooms melting, Ricordea shrinking and detaching, and Zoas melting away.
<... after you're done searching, reading, you'll understand why. How to put it/this: Your problems are obvious>

<Likely "Palys">
do great, leathers do great, polyps do great. Tank has been up for two years and this started with just the Zoas 3 months ago. More recently, I have a separate soft coral frag system, 200 g, 2200 gph pump, divided into 4 stair step tanks.
One section has mushrooms and leathers, one has polyps , other two house fish. My Ricordea are starting to shrivel and detach in this tank as well.
It has same readings and fixings except ph is 8.16 daytime, nitrates are at 5ppm, and the lighting is 120 watts led 24" off the tank over a 75g area.
Both systems have skimmers,
dsb, ample live rock.
<.... So... what are your choices? Provide or don't eliminate needed nutrients, and either remove the Ceriantharian, or the other mal-affected Cnidarian life. Keep reading. Bob Fenner>
re: Mushrooms and Zoanthids  10/10/13

What is WWM?
re: Mushrooms and Zoanthids... "I (don't) want to hold your ha ha ha ha ha hand!"   10/10/13

I see, wet web media, what should I read and which section can I find it in?
<... the indices; search tool... on all 12k some pages... the topics listed on your first query... B>
Re: Mushrooms and Zoanthids... comp. f's  10/12/13

So I read tons of post and answers on wwm. Thank you for the great knowledge base and for answering all these questions so there is such a vast reference to pull from. First I removed my tube anemone from my 75 and added carbon. I also added carbon to my 200 g frag system. Other than carbon and a water change, which is coming tomorrow, is there anything else
I can do to prevent this from happening again if and when it gets fixed?
<Mmm, yes; a few things. Principal amongst these is careful introduction of any new stinging-celled life... The SOP mentioned over and over to "mix water" back and forth from the isolation/quarantine with your display system you intend to move the animal/colony to>
Also are the palytoxins from plays poisonous to the Zoanthids?
<Yes; some more so than others>
And why are they not affecting any polyps or leathers? Thx
<They are better competitors... less susceptible to Terpenoid warfare.

Sick zoos 6/17/11
Hey guys,
I hope you are all doing well. I was wondering if you might be able to help me with something? I have a 250 gallon reef aquarium with very good, stable readings.
PH 7.9-8.1
Temp 78-79
Nitrate always less than 1
Po4 0.03
Calcium 410
Magnesium 1250-1300
Alk 7.5-8
Recently, I noticed one of my Zoanthid clusters starting to close up and turn kinda black...
<I see this>
The zoos have been in there a few months now and I have no idea what this might be but I am hoping to stop it before it gets worse.
I have attached a couple of photos of the troubled area. Would you be able to take a look and offer your opinion? Any advice would be much appreciated.
Thank you,
<Mmm, what is immediately above this Zoanthid colony? It appears that there is some Cyanobacterial growth to the right... Are any other organisms in this system showing overt signs of stress? What other stinging-celled life is around this area? What sort of (solid) supplementation do you do? Is it placed directly in the tank? Bob Fenner>

Re: Sick zoos -- 06/17/11
Hey Bob,
Thanks for getting back to me. See my answers below...
<Mmm, what is immediately above this Zoanthid colony?
***Ricordea mushrooms and another colony of zoos... the other zoos where added two weeks ago, but are easily 3 inches away. The Ric's are about 4inches away
<<Uhh... I see what is almost assuredly the issue in your system pic you sent along... have cropped the area... to the upper right there appears to be a healthy Euphylliid of some species. It is almost doubtless sending out mesenterial filaments, stinging the Zoanthid>
It appears that there
is some Cyanobacterial growth to the right...
***I am not certain that is Cyano? I have had Cyano before but it looked a lot "softer" than this stuff. This red stuff is quite hard. (I am assuming you are referring to the red stuff on the bit of white pipe behind the sick Zoos). I feed heavily, but skim aggressively and my po4 is never over 0.03 (I test weekly with a Hanna digital tester)... but obviously you would know this better than I... so maybe it is Cyano.
<Easy to scrape, take a look under a 'scope... or just feel... is it slimy?>
Are any other organisms in this system showing overt signs of stress?
***Actually just below the Zoos is a clam that is slowly recovering from a rough time. It was previously getting too much light ( at least I think that was the issue),
<I think it too was getting stung>
so I moved it to this location just below the sick Zoos...
(3 weeks ago maybe?). I also have an SPS on the other side of the tank that browned out last week (I got too close to him with Joes Juice trying to get Aiptasia I think). I have stopped using this and bought some peppermint shrimp. I should note that I only used Joes Juice in that one spot on the other side of the tank.
What other stinging-celled life is around this area?
***I have torch coral that is probably within 4 inches.
<<Ahh! This is IT>
It actually has grown into another colony of Zoos, and they seem to not bother each other too much. Is it possible a torch would touch one group of Zoos and have little effect, and then sting another group of zoos that is inches away and do so much damage?
<Yes, assuredly>
I never actually considered this... I have attached a tank shot so you can get an idea of the spacing.
What sort of (solid) supplementation do you do?
***The only regular form of supplementation I use is a calcium reactor. In the last month my co2 controller stopped working for a few days and I had to use reef builder to get the ALK back up, but that was it. It was added to the sump over a few days and has since stabilized...
<S/b fine>
Is it placed directly in the tank?
*** No.
Bob Fenner>
Thanks for your time Bob.
<Welcome Jas... I know it's a pain, but I'd be moving either the torch (with at least six inches, better a foot) or Zoanthid colony apart. BobF>

Re: Sick zoos
Thanks so much Bob. I'll adjust accordingly. If I could please ask just one follow up question? To the right of the torch coral, you see all the green Zoos that have grown directly into the Torch coral? They seem totally unaffected.
<Yes and yes>
So my question is, what makes this type of Zoos so tolerant, and the sick Zoos being so affected and showing so much stress after all this time? (almost overnight).
<Mmm, don't know, but I'll speculate that there is some sort of chemical communication and accommodation that occurs... but on what basis?>
The reason I ask is that I really like how the two have grown into each other, but of course I don't want to have stuff dying...
Thanks again
<Do try our new search tool (thanks Darrel) with this string: +Zoanthid and +Euphyllia compatibility
Here: http://wetwebmedia.com/Googlesearch.htm
Read the cached views. Bob Fenner>
Re: Sick zoos -- 06/17/11
Will do. Thanks Bob
<Welcome. B>

Zoanthids in a mixed community with Corallimorpharians and select LPS corals 9/1/10
Hello WWM Crew. Thanks for your availability today and lending an ear and a helping hand.
I have a scenario to present concerning my Zoanthids in a mixed community with Corallimorpharians and select LPS corals.
I have finally turned the corner on a 55 gallon reef in the never-ending battle with hair algae. I have shifted my lighting from 3 actinics and 1 daylight to a half-and-half configuration of two actinics and two 10,000k daylight power compacts. I have also recently added a Phosban 150 reactor, which seems to have stopped further algae proliferation cold (what green slimy gunk I remove, mostly stays removed. I am turning water over at the rate of about 35+ times the total system volume per hour. Here are the water parameters: ammonia - 0, nitrite - 0, nitrate - undetectable, specific gravity - 1.025, alkalinity - 2.5, pH - 8.1 (trying to stabilize at 8.3), temperature - 80 degrees, calcium - 440, phosphate - undetectable, silicate - not tested. I dose C-Balance A-B twice a week for calcium/alkalinity, Seachem's Reef Builder, Reef Buffer, Reef Complete and Reef Calcium usually once per week and as needed to maintain proper levels.
I also add 2 drops of Lugol's Solution twice weekly. I run 1 bag of Chemi-Pure Elite and 1 bag of Purigen, along with Seachem Matrix Carbon in an Emperor 400, specifically used for chemical filtration. I remove detritus with a 100 micron filter pad, changed weekly.
Fishes: Lawnmower Blenny (Salarias fasciatus), Bicolor Angel (Centropyge bicolor), Devil Damsel (Chrysiptera taupou), Cinnamon Clown (Amphiprion melanopus). There are currently no crustaceans or motile inverts in the tank. As for other inhabitants: 1 Cup Coral (Turbinaria peltata), 1 Duncan Coral (Duncanopsamia axifuga), both very healthy, directly fed and thriving; 2 yellow encrusting sponges which are growing quite rapidly; various Corallimorphs including Discosoma spp., Ricordea yuma, R..florida, and Rhodactis indosinensis, all thriving.
The problem is with 2 of the 4 Zoanthid colonies (all different species).
Two thrive and are open continually except at night, of course. Another fails to open all the way as the edges of the disk remain slightly curled up, and only a few of the polyps open at all on the fourth colony. These latter two colonies have failed to open all the way since introduction a couple of months ago, although they look healthy enough otherwise. I have
given these 2 "lagging" Zoanthid colonies a Lugol's seawater dip of about 30 minutes with 7 drops of solution, which seemed to have no effect.
<... I would move these non-performing Zoanthid colonies elsewhere. To another system>
The Bicolor Angel might ordinarily be a culprit in keeping the Zoanthids from expansion but many hours of observation has not revealed that he ever touches any of the invertebrates. (The fishes are well fed a varied diet.)
I do not see that water parameters are to blame either. Also, the Zoanthid colonies are placed on the opposite end of the tank from the mushrooms to reduce any potential effects of toxicity or aggression, and the LPS corals seem undeterred by the presence of either group. The Zoanthids have good water flow, reside in about the mid-section of the tank, and receive half of the lighting 12 hours per day and full lighting intensity about 8 additional hours. Any thoughts as to what might be causing two of the colonies to not fully expand or the edges of the disks to curl?
<They are "losing" to other Cnidarians here... likely the other Zoanthideans... if you leave them all present, there will likely be more chemical warfare stress and trouble than you'd like by the time they all (might) learn to get along. Please read here:
and here: http://wetwebmedia.com/cnidcompppt.htm
and the linked files above. Bob Fenner>
Thank you in advance for whatever insight you might have to offer.
Regards, from
David Bell
Thank you very much.
<Welcome David>
Am working on a Tomato Clownfish article. Will let you read...almost complete.
Regards, from
David Bell
<And you, BobF>

Zoo Colony - All Closed Up 2/4/2010
I've got a zoo colony (around 45 individuals) that has been closed up for the last 4 days. Well, 1-5 individuals will be open at any one time, but not the whole colony open as it has been for the last 1.5 months (4 weeks in QT & 2 weeks in display). The ones that are open seem to alternate from day to day and there seems to be no damage to any of the tissue or color change. The zoo color when closed is unchanged from day 1 too, so I think they're fine in that respect (i.e. not dying). I'm concerned about them remaining closed in the long term to lack of feeding activity.
<I see>
I have a 120 gal display with a 150 gal refugium/sump (split down the middle).
Around 180 lbs of live rock in display & 80 lbs in the refugium. 560 watts PC and 1,200gph water turn-over. I run Aqua C EV180 skimmer, UV, Ozone, calc reactor and all water param.s are good (8.24 ph, 1.025 salinity, 10-11 dKH, 78.5 temp, less than 10ppm nitrates, RO water and regular supplements. I haven't measured calc or Mag in a little while, but all other inhabitants fully extended, open, active, etc. (I'll get to those later).
The Zoanthids were the last addition to my tank --
<Ahh, what other Cnidarian life is present?>

no changes since the zoo went to QT in livestock, equipment, etc. (just routine maintenance). The Zoanthids are 10' from the surface and 8' from the nearest inhabitant. I did notice some very small snails in the rock with the Zoanthids in qt, but they didn't seem to be bothering them in there.
<Mmm, I would have excluded them/these>

They were very small (similar to pod size) -- had a small oval shell with very long antennae in relation to their body. The shell was so small; I actually thought they were some type of sea slug or Nudibranch at first glance.
<Even potentially worse>

My own personal diagnosis at this point is chemical warfare.
<Is a possibility>
No changes like introduction of livestock, bulb replacement, water change, flow direction change, etc., but something clearly happened 4 days ago to cause them to all close. Accumulation of chemicals until it reached 'x' level 4 days ago is all I can assume at this point.
I have 3 rose bta's (1 that's split a couple times & the prime suspect), frogspawn (the closest inhabitant to Zoanthid 8' away), scrolling plate coral, several xenia, 2 colts, 3 polyp colonies and several reef safe fish. The bta's are my suspect #1 --
<Actually, I'd give top mark to the Euphyllia>

they're all 14+ inches away, but I know they doesn't mean too much. 2 have moved slightly, but nothing significant as far as contact with anything else, but I assume this too could indicate some agitation I guess.
Here's what I've done in the last 2 days -- 40 gal water change, cleaned out skimmer & added charcoal into a fluidized media bed.
Water changes and skimmer cleaning I do regularly. I don't normally run charcoal/carbon. Would you recommend any other actions or suggestions?
<Mmm, possibly... move the Zoanthid colony elsewhere... back to the quarantine... Re-introduce slowly through water exchanges twixt the QT and DT>
I'm heading out of town for the week on Sat, so I want to make any changes asap. The house sitter will/can only do feedings.
<And read here when you have time: http://wetwebmedia.com/cnidcompppt.htm
and: http://wetwebmedia.com/zoanthidcompfaqs.htm
and the linked files where you lead yourself. Bob Fenner>

Palythoa/Zoanthid Malady - 03/30/08 Hey crew, <<Hey, Scott>> I love what you do and I hope to be as accomplished someday! <<Thank you for the kind words>> I had an issue that is still haunting me and I was wondering if you might be able to shed some light on it? <<Will try>> Here's a quick break down of my tank: Ammonia, Nitrates, Nitrites = 0 pH: 8.2 SG: 1.023 (currently raising to 1.026) KH: 11 Ca: 380 (raising this too!) Temp: 78 92 gallon with 1 250w Halide and 225 watts worth of VHO's. 20 times turnover for flow; sump with Chaeto and I'm currently running active carbon. I currently have two Leathers, two Blastos, chili cactus and some mushrooms along with several species of Zoanthids and Palythoa. <<Quite the noxious mix>> I bought a package of exotic Zoanthids and Palythoa. They all came healthy and happy, some opening up within 10 minutes of being in my tank. The reason I'm writing is because the one Paly I didn't want to lose died on me and I can't figure out why. <<Oh?>> It's been about a month now and everything else is doing fantastic. I placed the Paly on the sand bed 6" offset from the halide bulb. The Paly opened up immediately and stayed happy for about a week. I noticed the oral disc turning white and figured it was pretty stressed so I moved it to a higher flow area on the sand bed. It closed immediately with the move and developed large transparent bubbles on its body. <<Mmm…>> I then pulled it out and removed the bubbles (bad move) with tweezers and placed it back in. <<Ideally…this specimen should have been moved to quarantine>> It soon had a brown blotchy spot where the bubbles had been so I assume the Paly developed an infection. <<It likely had some type of bacterial malady from the start…and it's likely luck that kept it from spreading to the other colonies>> It was eaten by my wrasse the next day <<..! Strange>> so I also assume it must have been rotting because my wrasse hasn't touched any of my other healthy Zoanthids or Paly's. <<Hmm, I wouldn't expect this fish to eat these organisms at all…perhaps what was affecting the Palythoa was some form of parasite…and something of interest to the wrasse>> I was also running Caulerpa in my sump at the time which I now know wasn't very smart. <<…?>> I have two main questions. What should I have done with the Paly I lost as soon as I had seen the oral disc turning white? <<Removal to quarantine to segregate the infected specimen from healthy stock…and possible treatment via "dips." Animals will behave differently to different methods, and I never feel "freshwater" dips to be appropriate for corals…best to dip in clean and aged saltwater, with iodine, or a manufactured coral dip like that offered by Tropic Marin, in my opinion. Do search our site re "coral dip" for examples/other's opinions re>> What do you think the clear bubbles could have been? <<Don't know really, trapped gases maybe…generated by deterioration/decomposition>> It was about 5-6 inches away from an Echinata. <<Ah, Acanthastrea echinata? A clue, possibly>> Do they have sweepers? <<Indeed…very powerful…and can be far reaching>> Secondly, I have another Paly that has all the sudden started to act funny. It's body has shrunk significantly, but still opens up. <<Mmm, do you feed these animals?>> Should I move it or get it out of the tank? <<If the only symptom/observation is its getting smaller, no…but do keep an eye on it>> Another case of allelopathy? <<Maybe so…perhaps more carbon is needed on this system…or perhaps what you have needs to be changed out more often. I think the addition of some Poly-Filter would prove beneficial here, as well>> Thank you for your time, Scott <<Regards, EricR>>

Losing my zoos! -02/27/08 Hi Guys! <a gal here :-)> I have a 72 gallon reef with a large variety of corals. I have frogspawn, trumpets, Acans. lords, toadstool leather, Crocea clam, mushrooms, zoos, open brain, doughnut coral, other assorted leathers, green star polyps, and some Ricordea. They all survive happily together. <Uh huh, ok> I know that it is hard to meet the needs of all these varieties of corals, but they are all thriving successfully except my zoos and the inexpensive mushrooms. It seems like every six months or so my zoos and mushrooms fail to open and die off. Eventually, they start to come back, thrive successfully, and multiply. I am wondering if this is a natural cycle of some sort of if I am lacking in some kind of nutrient. <Or this is the result of ongoing coral warfare...> I also have an assortment of fish in the tank. A Tomini Tang, 4 Chromis damsels, blue Fiji devil, pygmy angel, clown goby, percula, along with 2 peppermint shrimp, 1 harlequin shrimp, and 1 bristle star and hundreds of tiny nuisance stars. The pH is 8.2, temp is 75.4-77, nitrates not detectable, phosphates are zero, calcium is 460, KH is 8 drops. I do weekly water changes of 5 gallons using RO water and Reef Crystals salt. The nutrients I add weekly are iodine, strontium, and trace elements. I feed the coral 3-4 times a week using Reef Bugs, Zooplankton, phytoplankton, and carnivore pellets. I have a wet/dry filter with a protein skimmer. I use 2 14,000K metal halides and 2 130watt 240/260 actinic 8 inches from the top of the tank. I have 2 1200 and 1 600 maxi jets for circulation and a chiller to maintain the temp. <In my opinion, you have too many different types of corals crammed into too small a space. Eventually, something has to give... I think your mushrooms and Zoanthids are paying the price here. Please see here to start: http://www.wetwebmedia.com/corlcompfaqs.htm > I would appreciate and help and suggestions to keep from losing my zoos and mushrooms. Thanks! Chris <De nada and good luck, Sara M.>

Zoanthids dissolving... small tank, Cnid. allelopathy, not reading...  - 10/30/2007 Help! I have been trying to get a handle on my Zoanthids that are shriveling and dying. I added them to my 29g <Part of the problem...> BioCube about 10 days ago and they opened right away and remained healthy looking for several days. I then decided to move them a little closer to the front of the tank, which I know was a bad move, but they seemed to have adapted so well I thought it would be o.k. After the move, only about half the polyps opened, two days later it got worse and some started to shrivel. My thoughts were they reacting poorly to the lighting (MH 175w, 15k, 10hrs per day. Polyps are about 30" from the bulb) so I moved them back to a more shaded area. During the move several dead polyps fell out! I have not target fed, but have done tank feeding of baby brine shrimp and DT's oyster eggs. <...> I did a 20% water change yesterday and things still look grim, even with them in a shaded location. I tested water today and all parameters are where they should be, except ph, which is usually runs 8.2 to 8.4, but today it is around 7.6! I will remedy this right away, but could this be the problem? I have several SPS, LPS and other softies that are doing just fine. <Oh yes...> Is it the intense MH lighting? The low ph? Lack of target feeding? Or, was it the move(s)? <None of the above> Thanks, Tyler. <The presence of "winning" other species of Cnidarians... Read here: http://wetwebmedia.com/zoanthidcompfaqs.htm and the linked files above. Bob Fenner>

Re: Zoanthids dissolving  11/06/07 Thanks for the below response. However I am concerned that Bob F. didn't understand my question and hope that there is someone else that can help me. <Hmm, I like your optimism, but Bob is our mentor. I doubt any of us would be able to help you much more than he can, but I'll give it a shot...> <<Mmm, please... I know little of use compared with the union of all we know here... our "Crew" plus the cumulative input of folks kind enough to write in. RMF>> I have a dying Zoanthid and want to try to save him. Bob F. provided a great link regarding Zoanthids, which would be great if I were considering buying a Zoanthid. He also indicated that the size of my tank, 29g, was part of the problem. As such, I have attached about 20 photos of tanks 34g and less that have not only zoa's with LPS & SPS, but with leathers as well. Can anyone help me? <Here's the problem; every coral is different. You can find Zoanthids which are virtually indestructible. I had such Zoanthids once. I actually TRIED to kill them in a 10g tank. I raised the salinity to >1.045. I turned off the lights for 2 weeks. I did everything imaginable just to see what they could survive. These were some tough Zoanthids! However, I also have Zoanthids that start to shrivel up at any swing of water chemistry or change of temp or lighting conditions. I had some of my Zoanthids shrivel apparently just because a mushroom near them died. The point is that there's a great range of sensitivity among corals of different species (or even within the same species from different environments). Just because you found pictures of some Zoanthids which can survive in a nano tank with other stony and soft corals, that doesn't mean yours can. Furthermore, suppose your Zoanthids were doing REALLY well, this might be bad news for your other corals. This is the trouble with nano tanks housing many different types of corals. In such a small space, coral warfare is intense and there are bound to be losers (if not immediately, then eventually). This happens in ALL confined environments with limited numbers of niches. The few species best fit to survive make it, the rest die off. It's a nearly inescapable phenomenon of nature. It even happens in large tanks... it just happens more slowly. When it happens especially slowly, we call it "old tank syndrome."> I really want to save this coral and am open to suggestions. <Move them to their own tank. If they're alone, you could possibly keep them in a tank as small as 10g (if you are quite diligent in maintaining the stability of the tank-- might help to do water changes with water from the larger tank.)> Tyler.
<Good luck,
Sara M.>

Button Polyp Issues ... comp., dis.     5/2/06 I hope you can steer me in the right direction as I have no idea what is going on with my Orange Button Polyps.  Only half of the colony will open up, and I have no explanation for this.  It is next to a purple ribbon Gorgonia and a yellow Sarcophyton, neither touching it. <Don't have to affect chemically...>   I understand chemical warfare is a strong possibility but I always change my carbon and poly pads along with a 5 gallon water change every Sunday.  My current setup is a 75 gallon tank with a 20 gallon sump.  Been running for nearly 3 years, and the button polyps have been around since the start!  My other tank inhabitants are as follows: Corals Colt 2 Sarcophyton elegans 1 Toadstool Brown Zoanthids Orange Button Polyps (Problem) Green Star Polyps Green Striped Mushrooms Hairy Mushrooms Neospongodes Kenya Tree Red Ricordea Montipora Capricornis Montipora Digita Montipora Encrusting Frogspawn Favia Hammer 2 purple Ribbon Gorgonia. Don't ask me how I stuffed these all in there but somehow I did it with out any of these corals touching each other.  A lot of them are small colonies and frags.   Fish Yellow Tang Perc Clown Springeri Pseudo Flame Angel (have not seen him picking) Mandarin Inverts Cleaner Shrimp Variety of Snails Variety of Hermits Filtration DSB and Refugium Coralife Superskimmer Lighting 384 watts of pc lighting Parameters Ammonia-0 Nitrite-0 Nitrate-2 SG- 1.025 Phosphate-0 Calcium- 430 Alkalinity- 9dkh I did see one of my Astrea snails hanging around the colony at night but they never opened back up and it has been three day's.  Should I start to worry yet or just let things be. <I'd do the latter... if anything, be moving this colony elsewhere>   They have never been touchy before so I have no idea why they would start now.  I also don't understand if it is chemical warfare why would half the colony be open why the other remains closed.  I also recently switched from B-ionic to C Balance about 5 days ago.  Can this be the problem? Do you have any other recommendations other than waiting it out? Thanks Eric <This is a not-untypical "garden variety" result of such stocking... Please read here: http://wetwebmedia.com/zoanthid.htm and the linked files at top, particularly on Compatibility. Bob Fenner>

Zoanthid Illness question    4/9/06   A friend of mine, who doesn't have internet access, recently purchased a colony of Zoanthids from a local LFS.  He has had them in his QT now for about a week, and noticed lesions have begun spreading over the colony.  He described them to me as small to medium sized, raised white bumps that are covering all surfaces.  The most affected polyps are slowly starting to remain closed.  This has also spread to some of the other colonies adjacent to the colony initially showing symptoms. <Not good> After doing searches and reading what references I have, I can only find one reference to what he described.  There is a thread on Reef Central that shows a picture of what he describes and they have labeled them "zoo pox". <Heee! Good name as any> I can not however, find any hard evidence of what this is, etiology or treatment.   <Not surprising> In the RC thread, the individuals have tried a variety of therapies including iodine, freshwater dips, drying, water changes, antibiotics, etc.  Most seems to be speculation and random attempts. <Bingo> The successful reports on the thread seem to involve letting the illness run its course and trying not to stress the animal with a variety of treatments. <I would do this as well... seek to maintain optimized, stable water quality... use activated carbon in the filter flow path... and Lugol's weekly... and be careful re allelopathic problems here. Likely the root cause... negative chemical interaction with extant cnidarians. Bob Fenner> Any advice would be appreciated. Steve

Polyps shutting down 9/8/05 I'm having trouble with some polyp colonies in my 125 gallon reef system!  The system was set up about 1 year ago and was doing great until about 1 1/2 months ago. Around this time, most of the polyp colonies closed in on themselves. The only colonies that seem to be thriving are the yellow polyps which continue  to open wide and ,in fact, are spreading! <When one coral is thriving while others are suffering, it is a good indication that the thriving coral is actually winning a chemical battle against the others.  Water changes and carbon are often helpful, but sometimes removal of the offender is required.> I have many Ricordea in the tank as  well as some leather coral which also seem to be doing well. I do have a hammer coral that has drawn in somewhat . I do not know the scientific names of the  polyps. I bought them as frags and have been growing them out. I regularly test for calcium, ph, magnesium, alk, salinity, and iodine. All test are in the accepted ranges. Do you have any ideas why only the polyps are suffering? thanks C.B. Hough  <Possibilities other than chemical warfare include nipping by fish or the presence of a predator (look for small snails with a "checkerboard" pattern.)  Best Regards. AdamC.>

Yellow polyps and Zoanthids - No Problem Here! Hi crew:  <Hello Larry from KC.> I love your site and all the good information it contains.  I have a couple of questions but first let me give you my setup 29g tank with the following equipment: CPR Bak-Pak2 skimmer 220w pc lighting 2-Rio 600 powerheads 1-Zoomed power sweep 45 lbs of live rock 1 1/2 to 2" of crushed coral and I do 15% water change every 2 weeks Tank inhabitants are: 1-Perc clown 1-Emerald crab 6- Bumblebee snails 12-Astrea snails 12-Hermit crabs 1-Green star polyp rock (over 150 polyps) 1-Blue mushroom rock(14 Shrooms) 1-Yellow polyp rock(8 polyps) 1-Brown/Green Zoanthid frag(10 days in system) Tank parameters: Ammon-0 Nitrites-0 Nitrates-0 PH-8.4 Temp-76 ALK-14.4Kdh Calcium-325 I noticed the other day that my skimmer wasn't skimming well, I discovered that the airline to the powerhead was clogged. Replaced airline and skimmer working great.  My mushrooms and green stars are doing great but my yellow polyps and the Zoanthids just barely open up. Could this be a result of poor skimming or something else? Also, is my ALK at 14.4 too high or is it ok? Too much confusion on proper levels for this. Any suggestions for helping my yellow polyps and Zoanthids would be great. Thanks and keep up the good work.  <Sounds like you are doing everything right. I would try weekly feedings of DT's phytoplankton or Cyclop-eeze. James (Salty Dog)> 
Re: Yellow polyp and Zoanthids
Hello again: Well, it's been a couple of more days and my Zoanthids have not opened up at all. I don't see that feeding would do anything if they are not opened. I've been reading that normal parameters for Zoanthids have ALK between 8-12Kdh.Could the problem be with my ALK at 14.4Kdh? Is there a way I could lower it to see if that helps? I don't want to lose these. I always feel bad when anything dies because I feel that I failed in my responsibilities. <Larry, you have about 7.5 watts per gallon on the 29.  I think it's a bit much for the polyps and zoos. I would try moving them to an area in the tank where they are not in direct lighting and see if that changes anything in a couple days.  I don't think lowering your dKH is going to help any, it's really not that high.  James (Salty Dog)> HELP!!!!
Re: Yellow polyp and Zoanthids
James: After reading more about KALK, I think I have been adding it incorrectly. I mix 1tsp in 2 gals of RO water and siphon off the clear top portion. I add it at night after the lights go out, but I just pour in what is needed to top off the tank. Should I actually be dripping it in during the entire night? Might I be spiking my PH by doing it this way? <You certainly will spike the ph.  It has to be dripped.>Maybe this is causing my problem? I will reduce my lighting and see what happens. I also intend to upgrade to a 225g tank later this year. Thanks for your help.<You're welcome> Larry

Adding Zoos! I am going to be adding 2 coral rocks with Zoanthid polyps on them to my aquarium. <Nice additions to a reef tank!> In reading, I understand that Zoanthids contain a poison that can be deadly if it gets into my bloodstream. How is the best way to get these into my 55 gal. aquarium that is already established? <I'd simply add the "Zoos" to your tank on the rock that they are attached to. Acclimate to your system like you would any other animal. Given time and acceptable conditions, these hardy inverts will spread and grow with little intervention required by the hobbyist! Hope that you enjoy the color and diversity they bring. Good luck! Regards, Scott F>

Orange Zoanthid 12/5/03 hello all,<howdy> I recently bought a very nice rock that has both colony of  star polyps and some orange Zoanthids on it. However, the star polyps are encroaching on the Zoanthids and so I want to trim the star polyps back. I have found this is normally very easy .  However I'm worried that when I try to remove the star polyps form the Zoanthids, they will tear and release Palytoxin.    <a legitimate but small concern. Wear gloves and use carbon in the tank and all will be fine for this small maneuver> I will wear gloves when I do this to be safe.  However, should I be  I worried about the effects of the toxin on the other organism in my tank? thanks! -matt <no worries... and time it with a water change afterwards if you like. Best regards, Anthony>

Zoanthid Question Thanks for the info. on bristle worms and green brittle stars. Just a question about a colony of brown star polyps I have in my tank. I have 55g. system w/ 4 fish.( two yellow tangs, a regal tang and a blue damsel.) I also have various crabs, snails , etc. The tank is lit by 160 W of fluorescent light and the bulbs are all new within the last six months. I have a colony of green and red mushrooms in there also which is doing great, it expands well and new mushrooms are sprouting. The brown polyps on the other hand are going the other direction. When I placed them in the tank about 3 months ago they did great. They opened up well and even appeared to be spreading. In the last two weeks, fewer and fewer polyps are coming out and as of today they are little more than bumps with hardly anything showing. I have done some water changes and have even started to run a Magnum filter with carbon. Nothing appears to be working. My next thought was to change the position of the colony in the tank. I don't overfeed and my nitrates are at about 20ppm NO3. What gets me is how the mushrooms, which I understand have similar requirements, are thriving while the polyps are dying. Any help you can offer would be appreciated. Bob's Answer: Hey Roman. Well you're right on target with moving the Polyps. Very likely they're under-circulated and very very likely involved in chemical warfare with the seemingly acquiescent mushrooms. Those Corallimorpharians are actually quite virulent in their campaign to take over all available hard space, and you'd do well to arrange "breaks" or demilitarized zones to prevent their spread/proximity to other stinging celled organisms. Place the brown polyps above, away from the Corallimorphs my friend.

Mushrooms and Zoanthids not faring well Hi, <cheers> I have a 100 gal diamond tank with 4-95watt VHO and 1-55watt PC lights. I have a wet/dry and skimmer.  <keep an eye on those nitrates with that wet/dry ;) > There are assorted fish plus a Ritteri, bubble <Hmm... how long have you had the Ritteri and the bubble is what? anemone or coral> and golden toadstool. All my water tests are good.  <good...?> I add iodine and Kent CB parts A and B to maintain alk and ph. Here's the problem. I have never been able to keep mushrooms and polyps alive!  <a common problem is mixed garden aquaria so severely assorted as your (anemone, LPS, Octocoral, etc)> The mushrooms start off great, grow for a month or so and then slowly die off. The polyps just stop opening and over several months die off. HELP! I don't understand. Dave <no worries here... it is quite natural and a sign that your tank is not as nutrient rich as most. Corallimorphs and Zoantharians usually hail from deeper, nutrient rich waters... where as your Ritteri and Toadstool hail from very shallow, lower nutrient waters. In the wild they are separated by perhaps more than 60' of water! It would be impossible to homogenize the parameters of a tank to suit the needs of both in the long run. Best regards, Anthony>

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