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FAQs about Zoanthid Disease Diagnosis  

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: Environmental,
(Pollution/Poisoning, Lighting...), Nutritional, Social (Allelopathy), 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

Too little/poor light? Too much current? Water quality out of whack? Predators possibly? Allelopathy from other Cnidarians?

Zoanthids looking crinkled???      2/6/15
Hi Bob and crew! Thanks again for reading. Your site and dedication are the best.
<Ah, welcome>
I started this colony with just three polyps 3 years ago in my 10 gallon nano tank.
<Very nice!>
When I set up my 225 gal a few years back I transferred them over and they exploded. There's are hundreds of polyps. They go through changes and phases from time to time but this crimped or crinkled aspect that some of the colony has is very odd.
<I see this... could be a few things going on here: Some sort of nutrient deprivation (do you have N, P, K?; What do you feed?), allelopathy (fighting amongst themselves, other Cnidarian life there), toxic reaction from... maybe the BGA in evidence here....>
This had been going on for two weeks. They all open up. The picture was taken after I fanned the rock so I was messing with them. Although they open the skirts look so odd. Strangely the skirts with a lot of green fluorescence seem to be the ones affected. I have scoured the site and I can't seem to find anything about this exact problem.
<Oh, the above rather common issues are covered>
Just people who's polyps won't open. I figure that it may be from allelopathy. Also, I don't have any nitrates right now. Water too clean? But no other of my other colonies are showing sins of distress at all nor are my corals. Let me know what this might be. It would be so sad to lose this gorgeous colony.
<Please have a (re) read here: http://www.wetwebmedia.com/ZoaDisDiagF.htm
and on to the linked files above in this series detailing Zoanthid Disease. Bob Fenner>

Re: Zoanthids looking crinkled???      2/7/16
Ok. Thank you Bob. In the picture what looks like BGA on my rocks is actually a dark red coraline algae.
<Really? Is it soft to touch? Slimy? Do you have a low power scope (with a USB connection!?) that you can take a look/see?>
I don't struggle with nuisance algae problems anymore (for now). I'm going to do some more reading on where you directed me. Thank you, Kinley
<And... we'll be chatting. BobF>
Re: Zoanthids looking crinkled???      2/7/16

Hi Bob. Thanks for taking an interest in this. I do not have a scope. Although, It used to be one of my favorite hobbies as a child.
I think I may have to invest in one.
<There are some FAB ones nowayears, so much tech. for such low prices. See Amazon.com alone>
Your reaction to my strange coralline algae is very similar to the reaction of my reef mentor. I had him come over and take a look at it 6 months ago due to some comments that people online made about it being Cyano. He's been in the business for 40 years. In fact he was the one that gave me your book. I live in the mountains of Oregon and I have absolutely no resources here other than him the internet and my books. He also thought it was Cyano until he touched it. it's very encrusted on to the rock and not slimy to the touch at all.
He agrees with me that it is in fact a rare type of coralline algae. I've gotten used to it over the years. It started in my 10 gallon nano tank, seeded from some live rock probably and I guess liked the conditions. In my 220 gallon it has covered everything. I would be very curious to hear your opinion. I have found a few others on line who have this too. luckily there's a lot of purple as well which does sort of balance out the visual aspect.
As far as my Zoanthids go, I believe you're theory that the nutrition is probably the problem. I have not fed the colony very much and now it's so large I'm sure it needs more. I also really don't have many nitrates or phosphates right now which is also why I don't have an algae problem.. ugh...its so hard to find the right balance.
<But so necessary>
I'm sending you a full tank shot so you can see how this weird type of coralline has spread all over.
<No pic attached>
<Cheers, BobF>

Zoas looking bad... several possibilities -- 06/09/10
<Umm, yeah!>
I have had a group or Zoas in my tank for prob 4-5 months they started off looking healthy and were always open, A month or so ago I noticed that they weren't opening up that much and getting some red algae slime over them
<You need to discern the cause/allowance for the BGA and solve it/this>

so I moved them onto a higher point in my tank hoping this may help. It seems to have made them worse and they are now not opening up at all and look very white.
<Apparently "bleached">
Tank parameters are normal,
I did have a problem awhile back with excess phosphates in the water but this now seems in check.
<How?... please see WWM re HPO4...>
All other fish. Corals appear ok.
The tank is 200L with a 30L sump I have a protein skimmer and run one Tunze Turbelle for water movement I am looking into getting a UV sterilizer to hopefully combat some of the algae prob
<Not a reasonable approach in general... see WWM re... >
that I am having on the tank glass and substrate. I run 2 150W 14000k Metal halides and 2 actinic PL Lamps
I have attached pics of before when they were healthy and a month back ( this is before I moved them up onto a higher point).
<Maybe start here altogether: http://wetwebmedia.com/zoahlthf2.htm
and the linked files above. Bob Fenner>

before after

Re: Zoas looking bad -- 06/9/10
Sorry a bit confused by your response
You need to discern the cause/allowance for the BGA and solve it/this> What does this mean I.e. BGA
<Read here: http://wetwebmedia.com/bluegralgae.htm
My tank parameters are : pH 8.2, Calcium 420, kH 8. Phosphates 0.25
<... see WWM re the last two>
I did have a problem awhile back with excess phosphates in the water but this now seems in check.
<How?... please see WWM re HPO4...> using a phosphate remover in the sump seemed to fix this
<... see WWM re>
I am looking into getting a UV sterilizer to hopefully combat some of the algae prob.
<Not a reasonable approach in general... see WWM re... > do you not recommend a sterilizer ?
<Keep reading. B>
Re: Zoas looking bad -- 06/9/10
Okay after reading your email a few times I think I get what you mean now, by BGA you mean I need to get rid of the red slime algae/find cause, They are now not covered in any algae, could this have caused them to die off.
I don't have any mechanical filtration so I will get some activated carbon in my sump hopefully this will help with the algae
Are they dead the attached pic is how they look today very bleached, can they recover. I have two smaller colonies in the tank and they all look the same, never saw any algae on them so I didn't think this was the problem.
I had a clam die a few weeks back, I moved him to a spot I thought was better but my Valentini puffer was able to get to him underneath and I think killed him, could the death of him effect the water?
I also read in one of your links that excess chemicals could be causing a problem but I only add - Calcium, Purple up
<See... re>
and Carbonate hardness powder. Should I be adding Iodine and anything else. I have a metal clamp on my pump holding the pipes together looks very rusty- could this be a problem.
Help I don't want them to kill any fish or other corals. I have Daisy SP and hammer corals xenia and lots of other Zoas that all look ok.
Also where do I find the book The Conscientious Marine Aquarist
<See Amazon.com>
Re: Zoas looking bad -- 06/10/10
Some of the articles i.e. the one by Michael Van Bibber, says to use purple up in supplementing calcium and iodine. Have had a look for FAQs against it but cant see it.
<Please put the string: "Purple+Up" (no spaces) in the search tool here:
and read the cached (highlighted) views>
What is wrong with a KH of 8, my test kit states this value is ok
<It is...>
Should I be adding Iodine and anything else. I have a metal clamp on my pump holding the pipes together looks
very rusty- could this be a problem.
<Yes> ( yes to which one or is it both)
<The last... too much Fe2, Fe3 is toxic>
I don't have any mechanical filtration so I will get some activated carbon in my sump hopefully this will help with the algae
<Some> Can you suggest anything else as I've spent the day reading WW and this is what I came up with
<See here: http://wetwebmedia.com/marmechf.htm
and the linked files above>
Are they dead the attached pic
<Nothing attached this time, but can recover...>
is how they look today very bleached, can they recover ( can you answer this )
<Welcome. BobF>

Palythoa Polyps Shrinking 5/19/09
I have a lovely brown/pink Palythoa introduced to my 29-gallon cube about 5 weeks ago. The 8-polyp frag was initially very healthy - large heads approximately 1 cm in diameter, thick 3/4 inch long stalks and plump interconnecting mat fibers.
< Sounds nice. I'm a big Palythoa fan myself. >
I placed the colony near the bottom of the aquarium in a well lit area with good flow. The polyps responded well and accepted food readily. Within 10 days, the colony started reproducing rapidly, sprouting five new polyps that grew very quickly. Success - until about two weeks ago.
Very gradually, the polyps have started to shrink considerably - not retract, but actually physically shrink. Heads are now just 1/2 cm in diameter, the stalks have thinned and shortened and interconnecting mats have thinned. The healthiest polyp has actually grown up an adjoining rock approximately an inch and attached itself quite securely. I'm lighting with a single 40 watt 10 K and actinic compact fluorescent and all water parameters seem in order. I have added a second single tube standard 15-watt 50/50 10 K florescent and increased lighting hours hoping that this might be a lighting issue. My three other small Zoanthid colonies are thriving and growing - only this small Paly colony seems affected. So, some specific questions:
1) Does this sound like a lighting issue and does the colony simply need to be moved up to the top third of the tank, or is it more likely a nutrition/feeding deficiency that is causing this shrinkage?
< It does sound like a lighting issue. I would move the colony up closer to the light. If you do not see an improvement you may want to consider a lighting upgrade. >
2) If a move is in order, can I safely sever the now very thin mat connection with the "polyp on the move" with a razor while in the tank to allow movement of the main colony? It is not feasible to remove the two rocks and perform the surgery outside of the main system.
< Yes , you can use a clean razor to sever the mat. Please use caution when handling/cutting them. Some people have had extreme reactions to the toxins present in Zoanthids/Palythoas.
GA Jenkins >

Palythoa problem  11/16/05 Hi, About a month ago I purchased some Palythoa, and they were doing fine and were actually replicating until about two weeks ago. I first noticed one polyp near one end of the colony beginning to discolor, becoming darker than normal, and shriveling. It then began spreading to neighboring polyps. About one third of the colony has shriveled and died at this point, and while the opposite end of the colony is still multiplying, it looks as if the discoloration is beginning to present in the polyps closest to the die off region. <Good note, observation> I assume this is some sort of bacterial infection, but I really have no clue.   <Mmm, not necessarily, likely bacterial... perhaps environmental, predaceous...> Should I cut the colony in half and dispose of the discolored polyps to attempt to save the others?  <One route to go... do take care with exposure (yourself, skin, eyes) here... do this outside the system, toss any water, rinse the specimen before replacing> Should I try a freshwater dip, or iodine or something? <Could do this... in addition, instead of the surgery> I am using Kent Tech I for iodine, I don't know if you can make a dip out of that or not, <Yes> but I would like to make some attempt to save the remaining polyps. Thanks, Frank <Help me rest assured and read all the material we have archived on Zoanthids, starting here: http://www.wetwebmedia.com/zoanthid.htm and the linked files above. Bob Fenner> 

My Zoanthids are turning white - 10/19/2005 HI, <Hello Paul> I'm a newbie to reef keeping.  I've had a fish only marine tank before but now I've decided to move onto reef tanks.  Currently my tank is 4 month old and I have four fishes and various Zoanthids and mushrooms.  Following is my tank parameters: pH=8.3, ammonia=0, nitrite=0, nitrate=0, alkalinity=3.5meq, calcium=340 question I have is related to my Zoa.  I've had them for about a few months now and recently noticed that the oral disk on the Zoa are turning white.<A sure sign of stress.>  I've read that this is due to too much light <not necessarily> but I only have about 3.7 watts per gallon and I have all my Zo's on the lower half of the tank.  Tank is 75 gallon.  Please help.  Thanks. <Paul, please capitalize proper nouns and beginnings of sentences in the future.  That said, back to business.  The oral disks are turning white because they are expelling their Zooxanthellae.  Too much light can cause this but is not the only factor.  There is not enough info on your tank to be certain what is causing this.  What is your temp.?  Salinity?  Are the mushrooms touching them?  Try moving your Zoanthids further up in the tank (maybe midway though mine prefer the top).  The only absolute here is that they are not happy with their present environment. - Josh> Paul  
Re: My Zoanthids are turning white - 10/19/2005
Josh, <At your service now that I'm finally home from work.> Sorry about the grammar.<No problem and thank you for correcting on this query.>  Here is the information that you've asked for. 1) salinity=1.023 and temp=80.8 to 82.<Salinity is fine though it could come up slightly (1.024-1.025, gradually of course).  Temp. is a bit high though not terrible either (78 would be preferable, again gradually if you choose to do so).>  The tank temperature rises when the lights are on and drops during the night when the lights are off.<The nature of the beast I'm afraid.  My heater is only set at 73, but with the lights and pump I'm at a constant 78.1-78.5>  Other things I forgot to mention is that I have 70lbs. of live rock and 120lbs. of live sand.  The mushrooms are far way from the Zoa.  By the way, can strong water movement cause this?<Is this strong laminar flow or random and turbulent?  Zoanthids like a random, turbulent flow.  My Zoanthids tend to "bob and weave" a different direction every 5-10 seconds.>  My tank water is heavily circulated with two Seio power heads.  Please let me know what other tank parameters you need to know in order to better help you diagnose the root cause of my Zoanthids being stressed.  Thanks. <Sorry Paul, but nothing jumps out at me immediately.  Therefore, I have more questions to help me out.  Strong laminar flow would likely result in closed polyps, not this per se (but still of concern).  Are you using a skimmer?  What type of lights do you have?  How old are the bulbs?  Welcome to the world of reefing friend and do get back to me please. - Josh>   Paul  
Re: My Zoanthids are turning white  10/20/05
Josh, <Bleary eyed and at your service> I'm still at work and I just got back to my desk from the engineering lab.<Sounds like you could teach me a thing or two!> The water flow is mainly laminar since directions on Seio specifically says it cannot operate with any type of wave generator.<Not necessary friend.  Turbulent flow can be created many ways.  Please search the site RE this.>  I'm using Aqua C EV180 skimmer<A great skimmer/company> but it is producing dark skimmate far less than a cup a day.<How many per week?  Do contact them if you are disappointed.>  I have a 15 gallon sump with a refugium.  My refugium is only 5gallon with Chaeto and live rock frag.  I'm in a process of designing a bigger and better (hopefully) sump.  For lighting I have power compact.  I believe I have two 10000k and two actinic from Current USA.  Light bulbs are about 4 months old.  Do you think my calcium and alkalinity is too low<No.> and can this cause stress on Zoa?<It could but I do not believe this is your problem.  Zoanthids are some of the easiest and least demanding to begin with.  You seem mindful of water quality so I would look to water velocity (at least direct velocity) instead.  I would correct the laminar flow first, as you may well be beating them to death. - Josh>  Again thanks for your help! Paul   

Zoanthid Question Hi  <Hello Bruce> I have a 120 gallon tank, which has been operating for about 9 months. It contains a collection of soft and hard corals, and a few fish. All of the water parameters are within normal ranges. Metal halide lighting. 5% water changes weekly. Up until a week ago, everything was thriving. Then, two of the three polyp colonies I have began to shrivel up. One is completely gone. The other is close to that. The third is fine. Was wondering what might cause something like this to happen.  <How old are the bulbs? These should be changed yearly. Are you using a calcium supplement that contains strontium and magnesium? Iodide helps also. I've been having good luck using Cyclop-Eeze phytoplankton for my softies. I feed once a week. James (Salty Dog)> 

Aging lights? Poor polyp expansion 5/29/04 I have some very beautiful green button polyps that are seemingly taking a turn for the worst.  The polyps have been in my tank for about 8 months.  In this time, they have not been moved, and have been doing quite well (they have even propagated).  Within the last two days, they have become flaccid and small.  Nothing new has been added to the tank in the last few months, all chemical factors are within normal limits, and all other corals are doing fantastic (frogspawn, bubble, various mushrooms).  I performed a 25% water change, and it didn't help at all.  What am I doing wrong?  Could this be a light issue, or is this some sort of cycle the creature goes through?  Please let me know.  My email is XXXX@hotmail.com   Thank You Very Much Tim <from the general symptoms described, its tough to say. If its a physical or chemical parameter astray in the tank, something has to be the first to show signs of stress - perhaps your polyps are a beacon. In this case, I wonder if your lights are not aged (fluorescents over 10 months old?) or if the glass canopy hasn't got so dusty or crusty that it is dramatically reducing light? Some things to consider. Best regards, Anthony>

Brain Food, and Other Coral Concerns! Hi Bob! <Actually, Scott F. in today!> I have looked thru a lot of your articles, but this problem I couldn't find. It may be me. <Yeap.. it's you! Hah- just kidding!> We have a 125 gal. tank with a wet/dry filter, protein skimmer, chiller, and even bought a r/o unit with deionizer. It is a starter reef tank with 120lbs. live Fiji rock, Yellow Tang, 3 Spot Domino, 2 Clarkii Clowns, Yellow Polyps, Orange Button Polyps, Open Brain, Red Mushrooms, one Ricordea, and misc. snails, starfish, crabs, and shrimp.  <Nice mix> The problem is, our Orange Button Polyp which has tripled its size and is gorgeous has developed white spots on the front part of the cluster. They are only on the "stem" of the polyp. The polyp is still beautiful and shows absolutely no signs of distress, actually it is still producing polyps. The polyps on the front do stand real tall compared to the others, where the ones on the back make a ball shape. The only time they close is when the lights go off at night. They open readily when the lights come on. All other corals are totally clean. Please help me. We have had this polyp for 6 months and it is my favorite. <Hard to be 100 % certain. Possibly just a migration of pigment, but it could be anything from flatworms to some other pest, too. If the coral is otherwise reacting well, and appears healthy, I would not be too concerned at this point. Just observe carefully and let us know if you notice a decline in the coral's health at any point> I know I am being a pain, but could you also tell me the best thing to feed our Brain Coral and amount. Everyone I talk to disagrees and I haven't had much luck with the internet or books. Thank you sooooo much!!! Julie <You're NOT a pain, Julie! As far as feeding the Brain Coral is concerned, I'd use fine zooplankton-based foodstuffs, such as minced Mysis, krill, or other "meaty" foods. The newly-available frozen "Cyclop-eeze" is a great food for these species! Good luck! Regards, Scott F> 

Red Grape Algae...but not Hi Bob, Anthony, or any of you other mystery invert specialists on the Crew: <Whassup?> Quick question for you all... <Okey-dokey> I have a piece of rock with some yellow Parazoanthus "gracilis" polyps that I have had for over a year.  I have noticed that the polyps have been thinning a bit and couldn't really figure out why.   <many possibilities... often simply from lack of adequate water flow. If they have not been getting enough random turbulent or surging flow (or if they have been getting too much laminar) they will not extend so fully and fleshy and just dwindle in time or be encroached upon> Now I notice that something (I presume fauna, not flora) has begun to grow between the polyps.  I did not notice these "somethings" before as the growth started from the hidden rear of the rock.  Anyway, the creature(s) that are now growing start out looking exactly like the "grapes" on the algae that some call Red Grape Caulerpa but without the stalks of the algae.   <Botryocladia can also grow without stalks... may be the same> They have exactly the same color and translucent appearance as the algae.  I flipped the rock over and the older ones have turned a mottled brown on their tops.  Any idea what these might be?  Good, bad (at least in terms of being responsible for the waning of the "gracilis')? Thanks for all the info past present and future.  Take care, Greg <hmm... on this scant description, I cannot even see why you think it may be fauna and not flora. A pic would help here my friend. Anthony>

Zoanthid - 11/25/03 Hello,     I have had some coral branch rock with small green button polyps (563.jpg) which had been doing fine for some weeks. <Very nice pictures> Recently they closed up and remained that way while other polyps in the tank have not (other.jpgs)<Interesting> I noticed some fine "smoke" trails emanating from some of the polyps and a jellylike mass from at least one. <possible Zooxanthellae bail out or just some excrement. Not too sure here>  I have executed a partial water change of 30% and my chemical levels are good from the standpoint of what most others report (Ca 400ppm, etc.).  I am mystified as to what might be happening. Any suggestions? <What has changed or been added recently? So hard to say what the issue could be here. I would leave them be and be sure that there are no other corals near them that may be affecting their ability to expand. How old is the lighting??? Are you dosing anything?? ~Paul>  Thanks!       From Sunny Misawa Japan       Richard Schulde
Follow-up on closed Zoanthids - 11/25/03
Thanks for the quick reply. <We aim to please> Lighting is very new, in a 30 gallon reef, and runs up to 260w (2x65w Act., 2x65w 10k) depending on time of day. <Did the closing of these polyps coincide with the addition of these new lights?> I add some Tech-I and have a Firefish and lemon goby which I have fed some garlic and Metronidazole soaked food for illness. <Were the polyps open during this time??> they appear to have recovered and now only get straight food. <Good to hear> The other corals (hammer, red mushroom, polyps) have co-existed fine until now and no-one else seems to have any troubles. <Means nothing to the captive animal world. Corals use allelopathy plain and simple, as a form of territory control. Some limit coral growth through the release of terpenoids (explains the smell of some soft corals when touched or cut. Smell your hands after a fragging. Smell funny after???)Other corals use there feeding tentacles as a means of defense. (nematocysts - stinging cells) So never count out corals within as far away as six inches and in some cases even further. Everything is fine until one day one of your corals begins to decline rapidly. I am not saying this is definitely the cause...... just something to think about> One small group of 4-6 green polyps had broken loose from the rest and settled across the tank exhibits the same behavior which I think is odd as well. <Agreed. I would just leave things be for a while. How long have they been like this, again?? Don't move them, only dose what you are testing for. See if this helps. Keep the water changes up and do about 10% twice a week maybe even three times a week in case there is some pollutant. Otherwise these corals actually live in very extreme areas. High flow and sometimes no flow, exposed to air even in some cases. I have seen them in polluted stagnant backwater areas in many tropical areas.> I am thinking about removing them to a smaller tank alone where I can control conditions for them and see what happens. <I would wait. No need to add the stress of a new acclimation to the fold. Leave them for awhile and see what happens. If they start to disappear then maybe move them> Any other thoughts? <Lots, but lets just stick to the topic at hand, eh? Hehheheheeh> Thanks again! <Oh my pleasure indeed. You are most welcome. ~Paul> Rick

Green Button Polyp Problem I know green button polyps are supposed to be some of the hardiest polyps  around, but I am having some trouble with mine even though I have gorgonians  which are supposed to be difficult but are doing well. I have a 400W MH over  a 2ft deep 90gal tank the button polyps are on the bottom. The polyps are  multiplying and their are very healthy ones next to some that appear to be  burned with some white spots and signs of dissolving. What could this be  from? I do frequent water changes 20% every other week. Chemical tests are  normal no ammonia, nitrite or nitrate. I also have some green star polyps  that are not faring well the mat has receded a lot. Could their be hydrogen  sulfide pockets in my tank and how do you test for this? >> May be a biochemical reaction/competition with some other life form in your system... too much light... some sort of additive/supplement poisoning.... If there were sufficient H2S in your system, you'd smell it, see the blackening in your substrate, see bubbles coming out of it from anaerobic glycolysis... What I would do with the button polyps (Zoanthids), is move some of the colonies off to the sides (out of the direct blast of the MH(s)... and add a unit of Polyfilter, and Chemipure to your filter flow path... and take a long look at your supplement habits. Bob Fenner 

Zoanthids hi bob, it me again. sorry to consult you again. it not that I ask too much question. it because previously I got no one to consult until I got to know you. <Hopefully also reference works, listservs, other sites on the web...> I had brought some button polyped and yellow polyped. According to what you say Zoanthids are consider hardy species. <Most> but the button polyped that I previously brought is consider quite big in size. 3-4 week later, the size decreases. <Typical, not to worry> The water condition is ok. and I do not know the reason why it decrease in size. same apply to my yellow polyped. the number of yellow polyped had decrease. Q1. I had placed the button polyped on the aquarium floor and with light. the current is consider medium low. Is the placement correct ? Q2. Is the feeding the same as mushroom. If water condition is good, the it is not necessary to feed the polyped ? Q3. What is the cause of the reducing of size ? <Likely just adjusting to the conditions, newness of their new home... I would feed the polyps... as detailed on the site: www.WetWebMedia.com> * Anyway do you have book which talk about the detail about corals (environment it is found, lighting requirement, water current and more details) If have what is the name of the book. As I am staying in Singapore and marine aquarium is not so common here. It hardy to find lot of marine aquarium book here. Do you have any web site to recommend if I want to know more about the coral ? Thank again. Danny C. <Will be visiting SG in May and June... And yes to helping you help yourself with a suggested book or two. For sure you want to devour "The Modern Coral Reef Aquarium" by Fossa and Nielsen (their link is on the WWM links page) especially volume 1, and v.1 of the Baensch "Marine Atlas". You will greatly enjoy these books, and benefit from them. Bob Fenner>
Hi Bob, I've checked on line and in books for information regarding Zoanthids, but most of what I've found has been a repetition of the fact that they are hardy and easy to grow with little actual information on their care. I was hoping you could help me out here. <Hope to> I've been keeping a saltwater tank for about 6 months and am branching into the world of the reef tank. To start, I've added a Zoanthid colony. For the first two weeks, the Zoanthid seemed to be doing fine. Now, it's started to shrink. It is not opening up as much as he used to, but it is having new growths. Why is it shrinking? Is there anything I can do to prevent this? My tank setup. 40gal tall 78 degrees f SG = 1.025 Ph = 8.2 - 8.4 Ammonia = 0 Nitrite = >0.3 <this should be zero> Calcium = 450ppm kH = 11 2 -- 55 watt Power compacts 10,000k 1 -- 15 watt Actinic 03 fluorescent The Zoanthids are about 8 inches below the water surface (and therefore the lights) and are slightly below the power head so they are not directly in it's current. Thanks, Chad Bowser <Mmm, not much more to say that isn't posted on WWM: http://www.wetwebmedia.com/zoanthid.htm Your new colony may have just shrunk due to the moving... water seems okay, same with set-up. I would just give this grouping more time. Bob Fenner> 

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