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FAQs about Xeniid Disease Diagnosis

FAQs on Xeniid Disease: Xeniid Disease 1, Xeniid Health 2, Xeniid Health 3, Xeniid Hlth./Pests 4, Xeniid Hlth./Pests 5, Xeniid Hlth./Pests 6, Xeniid Hlth./Pests FAQs on Xeniid Disease by Category: Environment, Nutritional, Pathogenic (Infectious, parasitic), Predator/Pests, Trauma, Genetic, Treatments

Related Articles: Pulsing Soft Corals, Family Xeniidae

Related FAQs: Xeniid FAQs 1, Xeniid FAQs 2, Xeniid FAQs 3, Xeniid FAQs 4, Xeniid ID, Xeniid Behavior, Xeniid Selection, Xeniid Compatibility, Xeniid Systems, Xeniid Feeding, Xeniid Reproduction, Soft Coral Propagation, Soft Coral HealthAlcyoniids, Nephtheids, Dendronephthya, Paralcyoniids, Nidaliids,

...common problem with Xeniid corals, they seem to "melt" when in unfavorable conditions or after drastic changes in water parameters

All My Polyps are Closed!!? Anomalous Xeniid crash   5/24/10
Hello Crew,
I have been a big fan of this website for years, and I come here whenever I have an easy or tough question to answer. The wealth of knowledge on this site is second to none, and I appreciate having this resource available.
Here's my most recent issue:
I've had a reef tank set up for a little over 3 years (50 Gal display with 30g sump), with various polyps, and other soft corals, as well as some fish, snails, etc. Everything has been doing well, but I recently switched two things to my tank, and ALL my polyps have been closed since. It looks like the Pom Pom Xenia are all either dead or dying, as well. I'm hoping someone can help...
<Do be ready to scrape, remove the Xeniids if they're collapsing... or take out all else to some other system>
I have always had perfect levels (8.3, 0 nitrate, 0 phosphate, 480 cal., etc.), but was still having an algae issue. To combat that, I decided to add a Vortech MP10 to make sure I didn't have any dead areas (Have been running a Mag Drive 12 as main return with a SCWD, with a Maxi Jet with 1600 attachment in the tank). I also added two boxes worth of Hagen BioMax Filter Media in a section of my sump, just before the return pump.
<Both these changes, additions should be fine>
My goal with those was to get rid of any "crap" that kept getting pumped back into the main tank by the return pump. My levels are still pristine, algae is pretty much under control, and the clarity of my water is much better.
But, my polyps remain closed!?
Any ideas?
<Something else... but Pulsing Soft Corals can/do at times undergo population collapses... and the resultant chemical stew can be very toxic to other Cnidarians, fishes even>
Have I "purified" the water too much with the BioMax?
<No... this is a chemically inert material... for bacterial housing...>
I've tried different speeds with the MP10, and no change. I've also tried putting Coral Frenzy in a few times, and no change.
Any help is Greatly Appreciated.
<Again, the removal of the Xeniids... or all other livestock elsewhere... Water changes, use of carbon, spiffing up your skimmer can only do so much>
(if this helps, I also have a small amount of carbon filtration, Nova Extreme T5's, a protein skimmer, and a good amount of live rock)
<Do/es help>
<Bob Fenner>

Xenia hlth. issues -- 11/17/2009
<Hey Joshua! JustinN here tonight -- combining both your emails together for simplicity of response!>
Hey guys! So..I have a problem (go figure) and I thought I would ask the "Oh So Wise" Gurus lol.
<*Sagely* Ask away, my son. ;)>
I have a 90 gal salt tank with metal halide (sorry I can't think of how many watts right now, and I'm not home). I'm running two Remora Aqua-C protein skimmers, I have a 4 inch DSB, and two 600-gal Hydor Koralia powerheads. I know, I need to get some more circulation, I'm working on it and adding a sump tank.
<Is not completely stagnant, better than many other situations... the sump will help though.>
Anyway, I have a blue Xenia which I bought about 6 months ago and it has been doing great! Grew from one base to 3 major bases now.
<The true 'seaweed'>
Over the past week, the polyps just suddenly sagged and it has looked pathetic ever since. I am pretty sure it is dying, since this happened to another Xenia I had before I bought this one. It is slowly shrinking into itself.
<This does occur on occasion naturally, a wax-and-wane of the population, if you will>
I haven't added anything, and just got done with a 20% water change and it made no difference. I make my own salt water and test it before use, and it looked fine. Everything else seems to be doing ok as far as corals and fish go.
<What other corals are you housing here?>
I have been fighting a Cyano outbreak for months now, and it is not completely gone, but has been drastically reduced to mostly on the glass and sand top. I have tested for phosphates, nitrates and ammonia, all at zero. (of course, the Cyano would just consume whatever is available so I consider it a false negative).
The only think I have noticed is an outbreak of deep red algae, which I assume is a type of Cyano, covering the rocks very rapidly, including the rock with the Xenia.
<If it is slimy as well, is almost certain to be Cyano as well... comes in many shades.>
So, I have been doing water changes and siphoning out as much of it as I can, and it has helped but the Xenia has not improved. Any suggestions?
Need any more info??
Thanks guys for all your help!
Joshua Lucero
<Need a bit more info than this to advise.... which is conveniently provided here!>
Sorry, I re-read my last email and there is more information that I should have given. The Xenia are on a rock all by themselves and "upstream" from any other corals (about 6 inches from the nearest), so I don't think chemical warfare is the culprit.
<Mmm, can still be the case -- allelopathy is a chemical situation, carried by the waters of the tank -- sweeper tentacles and the such, direct Cnidarian stinging would be the issue in closer quarters... what corals are housed here?>
I dose periodically with "Fuel" from AquaVitro, to keep a decent flow of nutrients in the tank (About twice a month), my pH is about 8.3 my salinity is in the range it should be on my specific gravity tool.
<Salinity numbers are important here, please do provide.>
My alkalinity is high (too much buffer, but corrected with water change because my calcium levels dropped to about 140).
<140? Is this a mis-type? This is exceedingly low -- perhaps your buffer addition caused a precipitous event, and your water balance is still skewed? Have a look here -- http://www.wetwebmedia.com/alkalinity.htm and related subheadings.>
They are in a place of good flow that isn't just from one direction, and the only other thing I can think of is that I dosed with some Amquel to help neutralize some of the dissolved organics that are causing the BGA to bloom. Amquel shouldn't affect xenia though right??
Joshua Lucero
<Well Joshua, the Amquel shouldn't affect the Xenia, but I have heard more than one anecdotal story of people who've had inexplicable problems when using this product in a reef setting... Amquel's main purpose is the neutralization of Chlor(am)ines and Ammonia from new treatment water -- in a saltwater setting, you'll optimally be using RO (or preferably RO/DI) makeup water before mixing your own salt. Treating the tank itself with Amquel will do nothing to improve your Cyano issue, and may well exacerbate it. What's needed to defeat the Cyano, is additional water flow, and regular water changes with very clean water. Have a read through here:
and related subheadings. Let us know if you have any further questions! -JustinN>
Xenia hlth. issues -- 11/17/2009

Hey Justin! Thanks for the quick response!
<Glad to help!>
I agree with your assessment of Amquel, I talked to one of my LFS guys about it last night. I was under the impression that Amquel neutralized nitrates, nitrates, chlorine and ammonia, which is why I put it in the tank. Didn't realize that it does all of that simply by neutralizing the ammonia and chlorine...sad day. Anyway, he said he has had some customers have the same problems. In fact, it is his theory that anything that forms a slime coat maybe hazardous to photosynthetic inverts, as he has lost some corals because of that.
<I would agree with this assessment -- this is not the first I have heard
of problems with Amquel in a reef tank.>
Guess it's going in the trash because I use RODI water so there is no need for it.
My specific gravity is 1.022, and yes my calcium levels were very low.
<I would get this raised to 1.026 over the course of several days -- those within your care will love you for it!>
I guess I over did it on alkalinity lol.
<I'd say so! I'd work on re-balancing this sooner than later -- daily water changes to regain a control on ionic balance.>
I'll fix it right away by doing a few water changes and monitoring the balance of calcium/Alk.
<I'd go so far as to abstain from any kind of dosing in this critical time period -- get your water changes done to get your water back in balance.>
As far as corals go, here is what I have: 1 small green Sinularia, 1 purple/blue Ricordea, 2 red mushrooms, large cluster of Zoanthids, 2 clusters of green star polyps and a small Montipora. I have everything pretty well spaced out as far as I can in the tank.
Joshua Lucero
<This all should be fine -- the water conditions are far more likely the suspect here. Do let us know if you have further questions!>

Xeniid system/health Q's 3/19/07 Thanks so much for the advice. <I welcome you to our help in Bob's stead. GrahamT here.> <Heeeee! Welcome yourself! RMF> I will keep watching. I wonder if I could bother you with one or two more issues. <Well... I... guess so.> I cannot keep xenia. <You aren't alone, my friend. Many have problems with this coral. http://www.wetwebmedia.com/xeniidfaqs3.htm  > I know you have heard it before but I am determined.    <Good.> I keep trading Starpolyps for small pieces and came across some info I questioned.  I understood xenia to be one of the few (if any others) that do not participate in chemical warfare.    <Well, they participate, just usually on the receiving end. As I understand it, they don't broadcast their chemicals into the water column as most other warring parties do. They can still kill by direct contact, though. There are some good pieces available on the internet that document the war between soft and stony corals. There are very many more and better catalogued pieces at a nice library.> the piece I saw in Reef.com said they kill off Acropora easily.  Can you clear that up. <Just did, oops. See above.> Each time I add xenia it seems fine for the first 24 hours and then condenses to solid white polyps. My non-pulsing anthelia is reproducing and my xenia keeps turning into balls.    <Mmm, this is a clue, methinks. Anthelia is winning the one-sided war.> I keep playing with alkalinity and salinity making sure the rest of the reef does no suffer.    <There are those that swear by Xenia's need for iodine to thrive. I think that your water changes probably maintain high enough levels of iodine so that this is probably not the issue. I would consider adding some fresh carbon to the system and trying a small piece of xenia upstream (as it were) from the anthelia, though not in direct current. Sound do-able?> Do you have any suggestions for me? <Umm, yeah. (See above)> thanks Cathy <-GrahamT>

Dead Xenia   1/3/07 I am new to this site and have read much of your excellent info. <Welcome!  Glad you found us!  Mich with you today.>   I'm hoping someone can help me out with a minor disaster currently happening in my tank.   <Minor disaster...jumbo shrimp...oxymoron?> I have had a pulsing Xenia for about 1 month that was doing very well.   <OK.> Overnight, it crashed and never recovered (PH was good during the day, did not test after extended darkness though)  As soon as the Xenia started to go south, both of my shrimp (cleaner and peppermint) died.   <Likely something else caused the death of all three.> My fish all seem fine, water levels are fine, and polyps are fine.   <These organisms may be more tolerant to whatever took out the Xenia and the shrimp.> I have a 100 gallon with 330 watts of light.  Could the Xenia have emitted something toxic that affected the shrimp?   <Again, unlikely.  Xenia is a good bioassay organism in that it will warn you of a problem by promptly dying, sort of like a canary in a coal mine.>   Any help would be greatly appreciated as I'd really like to have Xenia again. <Sounds like a potential contamination event.  Source could have been internal or external to the system.  Is there anything missing from your system other than the Xenia and the shrimp?  Did anyone in the household "help out" by wiping the walls of the tank down with a cleaner such as Windex?  I would review your recent activities around the tank... this may help identify the source of the problem.  I think you should be able to keep Xenia at some point in the future, but I would not add Xenia for a while.>   minus the melting. <Yes, not pretty, ...and even worse smelling!> Thanks! <Welcome and good luck!  -Mich>

About Xenia... dis., comp.   8/23/06 I having problems to keep any species of xenia in my reef tank. I would like someone advanced aquarists to help me solve the problem.   I tried to keep a lots of different species xenia but no one can success. Water quality? <Possibly> Lighting? <Not likely> Water movement? <Could be> Nutrients? PH? I do everything but did not see the result. Still cannot keep xenia in my reef tank.   My tank size:   36"x18"x18" with 15gallons sump with feather Caulerpa filter with 24hrs daylight lighting. with Plenum and 4" 2mm sand bed. 20kg live rock in main tank.      equipments:   1 (Eheim) return pump 3396l/hr   2 (Seio) water movement pumps 2400/hr   1 (Aquanic) water movement pump 1500/hr   1 (AquaMedic) Skimmer with pump 2500L/hr   1 280watts chiller      This is my tank water parameter:   PH         - 8.3   Ammonia - 0mg/L   Nitrite      - 0mg/L   Total Nitrate - 20mg/L <A bit high... would keep no more than half this>   Phosphate  - 0mg/L   dKH         - 11-12dKH   salinity     - 1.0235 <Better near 1.025>   Temperature - 26.5C   Calcium       - 450mg/L   Magnesium  - 1300mg/L      * I use SeaChem Reef Plus twice a week to maintain the iodine and trace element, and Kalkwasser to makeup water.    <Might be something in how you're administering these last two>   Lighting:   1 14k T5   1 Actinic T5   1 12k  fluorescent (sera)   2 actinic fluorescents (Acadia)      Fishes:   1 yellow tang   1 blue hippo tang   2 clown fish   3 green Chromis   1 Sixline wrasse   1 flasher wrasse      others:   2 cleaner shrimps   1 blue legged hermit crab      corals:   LPSs: 1 open brain, 1 green galaxy.   soft coral : yellow polyps, different species buttons and different types of mushrooms.    <Very likely allelopathy with these other cnidarians>   Problem:   - every time I added new xenia into my tank the xenia not open sometime will melted within 2days.   - sometime the xenia looks unhappy and dry look then slowly die off.   -then I tried to buy the established xenia from the LFS. the polyps open very nice in the LFS established reef tank with only actinic light. <Don't need actinic...> When I put it in my tank 1st day still open but not like at the LFS. 2nd day the polyps open bigger then 1st day. 3rd and 4th day looks good polyps open nicely, but till 5th day it looks unhappy the polyps looks dry again.....:( is no reason every things is ok but only xenia. I really loves this coral but very hard to keep :( why? why? why?   - others coral in my tank doing very well and spreading very fast like button. Maybe I got no luck with xenia :(      Steve xxxxx <Mmm... I would try adding whatever Xeniid to a separate "go-between" tank, with only partial water from your system, the rest all new... adding some more tank water weekly... Please read on WWM re Pulsing Corals: http://www.wetwebmedia.com/xeniidarts.htm and the linked files above, as well as searching, reading re the terms mentioned above. Bob Fenner>
Re: About Xenia... dis., comp., using WWM   8/24/06
Dear FAQ Crew,    <Steve>   Thanks for your advice.   Having some more questions.:      1. You said my NO3 level 20mg/L a bit high. Have to reduce it more then half of this. <Yes>   Current tank system is using 5 ways to reduce the NO3 level. 1. Protein skimmer (AquaMedic Turboflotor), 2. Caulerpa refugium (24hrs lighting), 3. Plenum system at the main tank, 4. ALGONE pouch, and 5. 10% water change every week. Last time my tank NO3 level was more then 100mg/L, now reduced to 20mg/L only. And I using so many way that still can maintain at 20mg/L only, so how to reduce more then half of this?    <Mmm... add a DSB, other macro-algae... Please read here: http://www.wetwebmedia.com/nitratesmar.htm and the linked files above>   2. You ask me to increase the Spg to 1.025. Is that will shock the live stock? <No... do gradually... with water changes> Is that have to increase a bit by a bit between few days? My LFS told me Spg too high the fish will infected saltwater Ich, is that true? <To some extent, yes> My clown fishes sometime got white spots, the day after they will gone by itself. Few days later the white spots will come back and infected my clown fishes again. If I increase the Spg, the white spots can be come more serious?    <See WWM re Cryptocaryon... you seem to have a latent infestation... best to deal with this...>   3. You said must be something I administering Kalkwasser and SeaChem reef plus to course failed my Xeniid. <?... possibly an influence, yes> This is the method to I administering this two. I tested my tap water is no nitrate so I did not use RO water. I add dechlorinator to tap water and mixed with Kalkwasser powder let it settle for few hrs. Extract the clear layer of Kalkwasser and drip it to my tank at night. I apply the SeaChem reef plus twice a week. <To? I would introduce this only through water changes> when reef plus added to the tank, I'll disconnected the protein skimmer for 1 hr. I using reef plus to maintain the iodine and trace elements for Xeniid as GARF website.   Is the method have any problem?    <Yes, possibly>   4. If the calcium level of my tank is not a problem 450mg/L and the dKH also in the right level 11-12dKH, how can I increase the ph level up to 8.4 an above? <... there are a few ways... posted on WWM> Can I using Kalkwasser to push the ph up? <I would not> coz last time I using buffer, problem is buffer will push the dKH up as well till the dKH level up to 17dKH. <Bingo... time to send you again... back to reading... on WWM re Kalk, Alkalinity, pH...>   5. About Xeniid. At night is the Xeniid polyps will close and not expand? Is that normal?      Thanks again      Steve XXXXXX <Please, learn to, use WWM, the indices, search tool... Bob Fenner>

Xenia and Yellow Polyps...Health  5/16/06 Bob: <James with you today.> I'm a new salt water/reef enthusiast.    I only started three months ago with two tanks... a 20 gallon and a 55 gallon.    I have CoralLife Compact Florescence with dual tubes @ 65 watts (Dual Day Light 6700K/10000K and dual Actinic 420nm/460 nm).    I have moderate to heavy water flow.    I keep pH higher than 8.0, Specific Gravity around 1.025, temperature at 78 F, keep my Copper below 0.25 ppm (one tank is zero, one tank has trace from when I introduced a Blue Tang that had copper medication on it), Ammonia = Zero, Nitrites = Zero and Nitrates > 40 ppm.    I provide Iodine, calcium, vitamins and adjust pH with Carbonates. I have had great success with fish, crabs, shrimp and some invertebrates (urchins).     I introduced a yellow polyp about three weeks ago and it was doing well until this week when it did not seem to open anymore.   I feed them twice a week by squirting with a medicine dropper with commercial phytoplankton.     Since they stopped opening, I squirt them once or twice a day.      They seem to have lost some individual polyps, but they seem to be retracting rather than growing.      They are also darker in color....when I got them they were light yellow, now, they are brownish yellow.    Is this the end for them? Last Sunday, I purchased a Xenia from a local store that is 45 miles away. I have read that Xenias do not do well in transit so I elected to get it from this store.    They do not have guarantees so I picked up one (they said that the coral was mounted only two weeks ago).       They packed them in a double bag but were not very careful about not "crushing" the coral.    When we got home, the coral was "under the rock".    I acclimated it overnight (in the dark).     This morning, the Xenia looks contracted and no movement whatsoever.    There were pieces of it on the surrounding rock (like white spots and some small tissues).       Can you provide some insights as to what is going on.    My understanding is that Xenias do not need to be fed, that they are totally photosynthetic. I appreciate anything you can help me with. <First question before we go any further.  Is the coral in the tank you are getting a copper reading from?  If so, I believe that is your problem. James (Salty Dog)> Noli

Xenia Troubles  - 5/5/2006 Good day to all, <To you as well, Adam J with you tonight my friend.> Thank you for taking the time to help so many of us with your experiences. <Tis quite fun for me, you are welcome.> I have two questions that I hope you can offer your input on. <Will do my best.> Six days ago I was given a few fragments of Xenia from an established tank. <Okay'¦>   When I placed them in my QT they were looking great and pulsing well.  The following morning I attached them to some live rock fragments (superglue on the coralline they were attached to) turned the lights on and left for the day.  They may have been shocked by the lights: as on my return the tips were slightly white and they looked "insulted".   <That or possibly your acclimation procedure? Xeniids are quite sensitive to swift changes.> I moved them to a lower light position but they appear to be degrading each day and have not shown any desire to re-inflate and now have a brown slime cover.  The mother colony was very nice and it is a shame to loose these, but this is my first time with Xenia and to me they look too far gone.  Do you have an opinion? > your pic, it does appear this specimen has passed the point of no return I'm afraid.> QT data 96w PC on a 29gallon <Good.> ammonia 0 nitrite 0 nitrate 8 <All acceptable.> Alk 10 dKH ph 8.1 - 8.2 <A little low for Xeniids'¦.If I recall correctly I believe Mr. Calfo recommended keeping these at around 8.4-ish.> ca 380ppm temp 77 - 77.5 flow is moderate My second question is also for an opinion, there are many differing positions on DSBs. <Really two only'¦..but I know what you mean.>   I am going for nitrate reduction and the growth of critters in the substrate for supplementary food supply.  My plan is to place 5 inches (320lbs) of sugar fine oolitic in the 0.2 to 1.2 mm range in the display and refugium. <Sounds good.>   Some of the FAQs on the site state that less than 1mm grain size is too small and a blend from .5 to 2.5 mm is superior at 5 to 6 inches.   <Really? I tend to recommend and prefer fine sand as coarse sand seems to become a detritus trap.> I do have an option of placing sugar fine in the refugium and the larger substrate in the main tank, but the refugium floor is only 180 square inches and I am not sure I would see a NNR benefit with this small area.  Do you have an opinion on this as well? <I think you are okay at your present position.> Thank you for considering my questions, please have a great day. <You Robert
<Adam J.>

Xenia detaching 2/9/05 I really appreciated the website. I use it extensively. I bought a lovely piece of rock with three large Xenia stalks. They have been pumping and waving about and are quite beautiful. A few days ago I notice that one of them seemed to have a break in the stalk and this morning it had broken off altogether and was lying on the substrate, still pumping.  <Many possible reasons... not excluding a shrimp, crab or fish clipping it off> I replaced it in a crevice in the live rock hoping it would reattach since it still seems to be alive. Now today I notice that the largest of the remaining two stalks seems to be detaching itself and I fear the same fate for him.  <hmmm...> Other than that they seem quite healthy. I have searched the website and most of the questions seem to be about them not pumping or lesions or retracting/melting. I don't seem to find anything on them breaking off or detaching. Any words of wisdom? <Since they are still pulsing and re-attaching, it sounds like some creature is disturbing them... do watch at night with a red light> Also, I'd like to keep my pod population from being decimated but I don't have a sump. You suggested a pod cultivating kit but the website didn't give much information other than advertising a bottle of liquid pods, can't remember the name of it. <Without a refugium, you are mostly resigned to adding bottled supplements at times. Oceanpods.com or Seapods.com> Is it just a supplement you add to the tank or is it something you have to have refugium for? thanks for your help. Janie <Live cultures to boost your tank. Anthony :)>

Xenia Woes 8/2/04 Hi, I've been an avid reader of your forums, and CMA, and I would like to say what a great source of info!!  Any problems I have had so far, the forum has cleared, but I'm stumped with my xenia. <lets have at it! Tally ho> First a few tank facts: Its 34 gallons a 3 gallon sump where I have a DIY Schuran Jetskim 100. <fantastic> In the sump I also have a bag of activated carbon. <do change small amounts of carbon weekly instead of large amounts monthly for best results> Water movement is created by an Eheim powerhead, and I also have a Fluval 304 serving as extra bio filtration.  The Fluval is connected to a spray bar that creates a great current in the tank. Lighting consists of  2 x 20 Watt 18000 Kelvin fluorescents and an extra 20 watt actinic, making a total of 60 watts. <this is extremely low for keeping cnidarians animals (corals/anemones). Waayyy too much blue light here.  The blue is used mostly for aesthetics. A general rule of thumb is a minimum of 5 watts per gallon of daylight  for reef corals. And of the 40 watts of non-actinic here, they are not only 110 watts shy of the mark,  but also too heavy in blue (as 18k K) themselves. Zooxanthellate corals and polyps will slowly starve to  death under these lights> Water temp tends to be around 24.8, but warm weather drives it up to 26. Ammonia    0 Nitrite    0 Nitrate    10mg/l Calcium    320 mg/l Alkalinity  12dKH Salinity   1.023 <allow the ALK to fall to around 10dKH and then push the Ca up towards 400 ppm (no higher needed)  for better results> pH (lab tested 7 hours after lights were off, so "night" time) 8.2 <very fine> I dose daily iodine, and weekly I dose with tropic Marin pro-coral elements, so called 70 trace elements to cover all needs. Livestock are: maroon clown, bicolor blenny, <Hmm... do be very careful here: blennies in general are not at all reef safe. They are nibblers on coral> six-line wrasse, 4 turbo snails, 5 blue leg hermits, 2 lumps of Palythoa, and 2 mushrooms, decrepit xenia.  So that's about it. My problem is that my xenia does not seem to open. It stays shriveled, and is very slowly  dissolving away. I did a water change to see if things would improve, but no luck.  All the other animals are very happy, the hermits are even molting, and I've never seen the mushrooms so expanded. <the mushrooms are actually panning for light. A very conspicuous sign of low light here> The xenia is in bright light all the time. But the funny thing is that, there are a few pieces of loose xenia polyps around the tank, out of the main light and they seem fine, <variable tolerance... all will suffer in time> just the large clumps stay closed. Also another question, does the bicolor blenny feed on xenia, because,  I can't find a culprit, but it might be that the blenny nips the xenia then it is closed. <very possible> What could be the problem, I know my calcium is a bit low, so I will try and increase that,  but it must be another problem! <true... no biggie> Please help, Thanks Chris Browning <best regards my friend, Anthony>

Xenia health, survival I have tried to grow Xenia in the past but without much luck because of an overly aggressive Coral Beauty and Maroon Clown.  I sold the fish and now I am in the process of trying Xenia again.  This time the Xenia (silver branch) did spread from the rock it was on to the rock placed next to it (some splitting did occur on a few of the corals).  That's all that happened.  Then after a period of time (1-2 weeks the base of the Xenia began to turn white and eventually it dissolved. <many possible reasons for this my friend... most common are low or flat pH or ALK (under 8.3 and/or much under 10 dKH)... and aggression from other corals. Xeniids are weakly aggressive> Amazingly I have had good success growing both hard and soft corals of all varieties.  The corals I currently have include torch and frogspawn, several varieties of mushroom coral, star polyps, button polyps, leather coral and others.   <yikes... you just names most of the top 10 most aggressive corals <G>. Seriously, your Xenia could be suffering from this unnatural and aggressive "garden reef" mix of corals. Do a keyword search of our website from the index page wetwebmedia.com for "garden reef" or "allelopathy" to see FAQs on similar challenges> Everything is reproducing but the Xenia. My tank parameters are: 90 gal show + 50 gal (20 gal overflow holding and 30 gal refugium) 440 watts of VHO (220 actinic, 220 aqua sun) on the 90 gallon CPR Protein Skimmer Calcium + 450ppm <hmmm if this Calcium is an accurate reading, it is on the high end unnecessarily IMO... do be careful .> Specific Gravity 1.023 - 1.025 Temperature 76 - 78 degrees Alkalinity 3.2 mg/l Ammonia 0 Nitrate 0 <you can allow some nitrates to linger to help feed corals/Zooxanthellae... 5-10ppm is fine> Nitrite 0 PH 8.2 - 8.4 <if this is a daytime reading, do check to see how low your pH goes at night. No problem here... but do try to make a habit of maintaining 8.3 for a minimum round the clock> I test for PH, Alkalinity, Calcium and Specific Gravity on a weekly basis.  In addition to adding calcium and a buffer I generally add trace elements and phytoplankton when I perform water changes (weekly). <you have listed no corals above except maybe the leather in tiny amounts that will eat phytoplankton... do focus more on providing zooplankton as the vast majority of corals are carnivores> However I haven't added trace elements or phytoplankton for several weeks as I was being cautious of over dosing and starting a micro algae growth problem.   <yes... very good/wise and correct> I have a bunch of macro algae that is growing like crazy in my refugium.  I don't use any charcoal for filtration. In fact my filtration consists of a protein skimmer, macro algae and floss to catch debris before sending the water back to the aquarium.  The tank has been set up for a little more than 2 years. <all good> Any ideas of what is happening?   <perhaps the tank is mature enough and simply has too many aggressive competitors. Its really a lot for such a small volume of water> I really like the looks of the Xenia and want it to grow but so far not much luck. <do try establishing it in a refugium instead. They will pose no burden on plankton as they cannot eat organismally> Any help is appreciated, Craig Walker <best regards, Anthony>

Unhappy Xenia 5/29/04 Hi Crew, <howdy> I hope you are enjoying the holiday weekend.   <I succeeded in avoiding overeating... now to resist the leftovers. Yikes!> I am having a little trouble myself so hopefully you can help.  Over the past week my Xenia have been disintegrating little by little.  For about two months these captive-raised Xenia were (apparently) doing great.  They grew to the point they were crowded on the existing rock so they began splitting and migrating to neighboring rocks.  The rock in the center of the attached photo "Sick Xenia.jpg" is the original rock and you can see how they have spread to the neighboring brain coral skeleton and the other live rock.  The dying Xenia is difficult to make out but I have circled it in red.   <many possible reasons for this... two most common being 1)water quality (usually prolonged low pH and/or Alk: as defined by pH below 8.3 and ALK below 9 dKH)... and 2) a pathogenic infection from damage or from an unquarantined animal (fish, snail, another coral, etc) carrying it in. Please do QT all "wet" entries without exception - 4 weeks> A few days after the Xenia completely broke away from the parent colony, a few polyps of the parent began to wilt, then shrivel and disappear.  This has since spread to many other Xenia stalks.  The individual colonies in this photo previously appeared to be a continual, massive group of pulsing Xenia. Water parameters check ok (at least those I am able to measure: Temp = 79F, Salinity=1.0235, pH=8.1, Ammonia=0, Nitrite=0, Nitrate<5ppm, Alk=6, Ca=380) <if the ALK reading is in dKH it is scary low... if it is in meg/l then it is scary high. Your pH at 8.1 is also rather on the low end if this is a daytime reading... drops even lower at night. Do consider using or using more regularly Calcium Hydroxide to improve pH, ALK and Calcium levels> and I have not noticed any fish, coral or invert assaulting the healthy Xenia.  There is a "eyelash blenny terrorist" in the tank that I have seen chomp at the dead/dying Xenia but I have never seen it bother the "healthy" Xenia. (this blenny is a real nuisance but I have been unable to catch it in my 180g tank with all the rock). <blennies truly are not reef safe as you have noticed. Most are nippy at something. We have some great tips for trapping fishes in the archives... do a key phrase search ("trapping fish") with the Google search tool on the home page> Several changes did happen about the same time the Xenia began showing signs of stress so I am unsure if one of these change might be linked to the Xenia  's demise.  The following were added: * One tiny new Xenia frag (appeared to be the same type as what I already had. I did not specifically want this new Xenia but it was included in a SPS + soft coral pkg) * Toadstool leather * 3 tiny Acropora frags * Derasa clam * Synchiropus picturatus * Synchiropus splendidus <we harp on this often here at WWM, but QT is critical for all new livestock. Otherwise, adding non-quarantined fish is like playing Russian roulette... no body wins the game, some people just get to play a little bit longer. Too many pests, predators and diseases can be added this way. Please QT> In addition, I isolated the 20g refugium from flowing into the main tank for about 5 days to get a Cyano problem under control in the refugium and I removed the filter pad from the wet/dry and placed in directly in the main tank (Mandarin food - filter was full of 'pods).   <excellent> I also dosed the main tank with strontium for the first time.  The Seachem instructions on the dry strontium indicate it is ok to add the powder directly to the main tank so this is what I did.   <yes... to a strong stream, of water or dissolved> I cringed as I watched the granules travel past the Xenia though as I was unsure of the effects this short-term highly-concentrated local strontium level could have on the Xenia.   <no worries here> The toadstool coral was my only other guess at a possible cause for Xenia stress as I have read that Sarcophyton can release chemicals that are toxic to certain other corals.   <ironically... Sarcophytons in culture with Xeniids seem to benefit the Xeniids (see Borneman, or references in my Book of Coral Propagation to this)> You can see the relative placement of the toadstool in the photo "Sick Xenia1.jpg". <truly no harm here> A few days ago I performed a 32g water change, removed the PhosBan that had been in the filter for a few weeks and added activated carbon.  I have noticed no change in the Xenia since doing this.  The remaining Xenia are pulsing like normal and appear healthy except for 1-2 colonies, which have wilted, are darker in color and are not pulsing.   <Pulsatory function (ceasing) has been associated with low pH and low ALK> These colonies will eventually die / disappear and other "healthy" colony will then wilt. Do you have any ideas what could be wrong or suggestions for what I can do to reverse this trend?  I am planning another 32g water change for later today but, other than that, I do not know what else to do. Thank you, Greg <isolate some pieces in QT and improve water quality in the main display. Best of luck! Anthony>
Unhappy Xenia II 5/31/04 Anthony, Thank you for your help with my Xenia problem.   <always welcome my friend> I guess I should have mentioned this previously but I do QT all new fish for 4 weeks after only "normal" appearance is observed.   <excellent, but do this for all livestock that comes in. Each/all have the potential for carrying pests predators and disease (in their bag/system water if nothing else)> Corals have been the only exception to this rule as my QT has been dosed with CuSO4 so I could not place corals in this tank.   <Hmmm... QT should not have any calcareous substrates (no sand, coral skeletons, rock, gravel, etc.) as this absorbs and interferes with medicants. As such, there is little or no worries about copper after a water change> Since all my corals were aquacultured, I was (possibly erroneously) not as concerned about their QT. <very erroneously my friend... you are assuming that the places you get your aquacultured corals from also QT their fishes, corals, etc. and did not add something infected days, hours or minutes earlier to their tanks before you made your purchase. This is how most people get their tanks infected with nuisance and predatory flatworms, Ich, nuisance anemones, etc> I did recently purchase your book "Reef Invertebrates" and have read several chapters (kudos on the great book!) <ah, thanks kindly> but I have not yet read much about proper quarantine of corals.  \ <we have recent articles on this topic here on wetwebmedia.com (see Scott Fellman's piece). Our book coverage of corals with anemones other cnidarians will not appear until vol 3 (2005?). But still... in the reef invertebrates book you have, we make it clear, redundant at times, that QT is for all living organisms without exception. This is a common mistake my friend. No worries... just don't make a habit of ignoring it or you'll get burned bad ;)> I have read about using an iodine dip or Lugol's dip for hard corals <this is generally not necessary or recommended. It can stress healthy corals and has little effect on prevention> but I did not realize corals also required QT. Could coral QT be done in my 20g refugium or should I be concerned about water-borne diseases or parasites from the new corals? <the latter, mate... this is as much about hitchhiking pests and predators as it is water-borne diseases> I use a Kalkwasser reactor so I do dose Kalk regularly (I lose about 1.5 gallons per day to evaporation).  I just re-measured pH at 8.15 and Alk at 5.5 meq (after last night's 15% water change). <the ALK is rather high (this is whats keeping your Ca and perhaps pH flat). Do a large water change and seek to have more even keeled ratio of Ca and ALK (350-425 ppm Ca and 3-4 med/l ALK but neither high at the same time... difficult and potentially dangerous (precipitous reactions))> Despite having adequate carbonate reserves and Kalk dosing, this is the consistent pH reading I always measure.  Possibly my test kit (or my interpretation of color) is slightly off.   <perhaps... do use other types/brands of test kits for reference. If all similar, it could be accumulated CO2 in your well-insulated home (see much about this in the WWM archives)> My Seachem test kit indicates, "although NSW alkalinity is around 3-4 meq, aquarium alkalinity should be maintained between 4-6 meq" so I had always assumed my alk readings were in-spec.   <really 4 is fine/best. The higher end appeals to folks with enormous stony corals tanks or bio-loads> You indicated my readings are much too high.  Do you recommend I try to lower my alk?   <yes.> I suppose this might allow me to raise my Ca level above 400 ppm. <exactly my friend! If interested, I have an article in the archives called "Understanding Calcium and Alkalinity". Do a keyword search with the Google search tool from the wetwebmedia.com home page for such items> I appreciate any comments / advice you can provide.  Also, is there anything you recommend in addition to possibly adjusting alk, to keep my Xenia alive? <when in doubt... frequent water changes. Truly the single best thing you can do most often in times of trouble. Anthony>

Dying Xenia 4/28/04 I tried putting this on the 911 site Saturday.  I kind of wrote it wrong.  Where I put Iodine below I put ammonia by accident. Anyway, here is the problem: My pulsating branch Xenia is not looking good at all. I really need some help. I have read several Q and A's on this site about Xenia problems and how to fix. I have tried everything. It looks like he is melting. He was doing great for 5 months until then. It started last Sunday when I did a water change. The only thing I did differently this day was I did the water change with R/O DI water for the first time instead of dechlorinated tap water (had a brand new one of these delivered to me last Saturday). Made sure my measurements matched the tank before I put it in. Measurements in tank Amm 0, nitrite 0, Nitrate 10, PH 8.3 SG 1.025, temp 78, calcium 350. <all good> Been putting iodine in every night as I always have, I moved him about 12" away from a green star polyp coral in my tank to see if that would help (he was about 8" away prior). <indeed... green star polyp is extremely aggressive (chemically noxious as well)> I have put in a Poly Filter since then to see if that would help (I always use carbon also). I have not put anything new in the tank and I can't see any marks on him either. If I can't find the problem soon he will probably die. Any help will be appreciated.  Thanks, Tom <when in doubt... do a(nother) water change. And with Xenia... focus sharply on pH. If 8.3 is your daytime pH... then your pH is too low. Many Xenia stress below 8.3 which is occurring after your lights go out (aim for 8.4-8.6 by day and no lower than 8.3 by night... use Kalkwasser to help achieve this). Do consider and try. Best of luck, Anthony>
Dying Xenia II 5/2/04
Anthony - I am kind of running into a little jam on this one.  I have a cup coral (LPS) in the tank and it looks like he does not react too good to Kalk (I usually use Aragamilk to keep my calcium up).   <this is really not the problem (Kalk)... it must be the way you are delivering it my friend. Millions of gallons of seawater and decades of aquarium use can't be wrong ;)> He usually opens right up, but when I started putting the Kalk in he did not open as much as he usually does.   <added too much or too fast. Do try smaller shots or a slower drip> This happened in the past with this guy also (he is fine with just Aragamilk, the Xenia used to be also).   <FWIW, I have little regard for the efficacy of Aragamilk> Also - I have tested my PH several times before the lights came on in the morning and it is 8.3.  I have an AquaFuge hang on refugium and keep that light on 24/7. I heard that helps to stabilize the ph in the main tank when the lights go down.   <true> So my tank is pretty much 8.3 all the time (if that is possible, could be my test kit).  I have another question for you.  Just thought of this.  When I put the R/O water in the tank for the first time I used Kent OSMO Prep to buffer the water.  I never used this before.  Always used Kent SuperBuffer.  Have you ever heard of any adverse effects that OSMO Prep may have on Xenia? <no information good or bad on it> Just to keep you updated on my tank, the measurements are all the same as they were before, except my nitrates are almost 0.  Using R/O DI water took them down pretty quick.  Thanks in advance for any help you can give me.  FYI - The Xenia is still hanging on, but nowhere near where he was before. Tom   <many possibilities still... finessing iodine, RedOx levels, allelopathy. The challenges of a 3-D environment. Anthony>
Dying Xenia III 5/3/04
Thanks again Anthony.  This hobby is definitely a learning experience. <like life... enjoy the journey :) Anthony>

Melting Xeniids & Flatworms Galore Hi there WWM Crew. <Hey, Mike G with you tonight> Have been enjoying your site and links but have run into a couple of problems. To begin, let me give you the stats on the tank: <I personally thank you for giving me the stats on your tank. Out of many, many emails I have answered today, you are the first to provide such information. :-) > SG 1.025 <Fine> pH 8.0 in the morning (before lights come on) and 8.2 5 hours after lights on.. <You might want to find a way to remedy this. That is a large pH swing, and would cause undue stress to your pets.> NO2 (0) <Perfect> NO3 (20)  <Okay, but it could be a bit lower> NH3 (0)  <Perfect> Tank is set up with l MH l4000K and 2 65W 03 actinic along with a Bak Pak 2R protein skimmer that's skimming l/2 C of green stuff a day. Tank temp. fluctuates between 77.5 to 80F degrees lately. Water change weekly 15 gals. Sometimes time doesn't permit, and water gets changed every 2 weeks. <Sounds fine. I am left wondering how large your tank is, though.> Problem l: For some reason, my pulsing xenias are dying (melting) and I can't figure out why. Have had these Xenias now for almost 2 years pulsing and dividing away and now...  What's going on here? <This is a common problem with Xeniid corals, they seem to "melt" when in unfavorable conditions or after drastic changes in water parameters. Take a gander at the following link, namely the topic "Xenia Health" about 3/4 down the page. http://www.wetwebmedia.com/xeniidfaqs3.htm  > Problem 2: My frog spawn frag (originally only 2 heads - now 6 heads) has been invaded with oval shaped pumpkin colored flatworms - have no idea where they came from as I do quarantine any and all going into the main tank. I've  read that they come and go But, now they've migrated to my pagoda coral and I really don't want it to take over the whole tank (60 gal)!  <Ah, there we go, 60 gallons. Flatworms have a habit of overrunning marine aquaria.> On my next water change or sooner, can I do a fresh water dip or Lugol's iodine dip on these two corals without harming them and hopefully getting rid of the flatworms?  <That is exactly what I would have recommended you do.> Thank you for your help/advice. <Best of luck, Mike G>

Save the Xenia? - 8/28/03 Hello, I've been having a problem with my xenia.  When I first received it, the original xenia  colony grew and spread rapidly throughout the tank (and was pulsing). However, over the last month, the xenia has slowly stopped pulsing, no longer extends, and even the small brown polyps at the ends of the stalks look like they are deteriorating. <predation or water quality likely> The main xenia stalks have completely shrunken and now all that's left are the individual stalks. The strange part is that everything else in the tank seems to be doing quite well (leather, gorgonian, many mushrooms and polyps) <actually... the four Cnidarian groups you just mentioned easily make the top 20 list of most aggressive corals regarding noxious exudations. Your Xenia may very well be suffering from their aggression if your water change schedule and or chemical filtration has been light. Weekly water changes and small weekly/monthly changes of carbon are ideal> and  I've gotten coralline algae growing on the live rock and back of tank. <not a fair comparison... these are all completely unrelated organisms with different tolerances> I realize xenia require phytoplankton/light/iodine - I've recently started adding DT's (the problem started at least 1 month before this, though), Seachem reef iodide, there are 2 x 96 W power compacts (6500 and actinic O3).   <you are mistaken my friend... Xenia cannot even eat phytoplankton. They do not have fully formed digestive systems to eat organismal prey. In fact, they are one of the closest corals to being autotrophic as it gets... getting all they need from light and feeding by absorption> SG is 1.021-1.022.   <hmmm... the salinity is a little low. For coral keeping, please do stay at full strength seawater 1.024-1.026. A dilution in turn dilutes coral sustenance> Recently I've seen a white powder that doesn't dissolve when I make up new water w/ instant ocean (didn't see this a few months ago when the bag of salt was opened).  I also was trying to raise Ca2+ last month w/ Kalk and Seachem  calcium-gluconate, and also have used B-ionic.  I've also been doing 5 g water changes (30g tank) every 2-3 wks. Any suggestions for saving the xenia? <if the problem is not predation (tiny worms, snails etc).. then look at your pH and ALK. Xenia are very strict about high pH. Daytime readings should be *.4 or higher... and watch that night/morning readings do not dip below 8.3 (they will often stop pulsing like clockwork). Alk should be in the range of 8-12 dKH (preferably towards the higher end. Ca will be fine at a modest 350-400 ppm> Thanks for any advice. Ben <please take the time to read through our archives on this subject. Go to the main page www.wetwebmedia.com and type in Xenia into the Google search tool for our site at the bottom of the page. Best regards, Anthony>

Xenia Health Hello, I have had xenia flourishing in my tank for over six months and have shared many frags with others.  <very good to hear...especially the sharing part <G>> Three days ago, I noticed that several of the stalks have what appears to be some sort of injury...looks like some sort of wound with this crusty yellowish stuff. <Hmmm.... caution here. Can be rapidly infectious> The affected stalks appear to be dying and several more stalks look to be in peril each day. I have seen xenia crash or "melt down" in other tanks (as it seems to be famous for) but this is very different. I have tried to see if any of the tank mates are bothering the xenia but I don't see any. Everything else in the tank is as happy as ever. Any ideas? Thanks kindly, Jonathan Bush <yep... they are quite sensitive to water quality. A dip below 8.3 in pH or very low ALK (below 8 dKH) is often the culprit. Also lack of water changes and Iodine supplementation (colony reaches critical mass as nutrients are depleted with growth). And lastly... chemical burns from the accumulation of noxious allelopathic compounds in the water from aggressive corals (star polyps, mushrooms, colt coral, etc). Weekly carbon changes in stead of monthly, aggressive skimming, PolyFilters here for this. Best regards, Anthony> Jonathan Bush

Xenia Lost Their Zip! Hi Guys <Scott F. your guy tonight> I have Pulse Xenia and white star and some metallic green xenia all other corals bubbles, leathers and other polyps are quite happy. But the Xenia never seem to grow and the pulse stays contracted but still pulse? The green xenia looks like it may be dying off. Water quality is fine ,will additional strontium help? <I have not heard of strontium supplementation being beneficial to this species...> or am I missing something else? Thanks, Tim <Well, Tim- there are all sorts of theories as to what makes Xenia pulse. Some hobbyists swear that iodine supplementation is the key, others feel that light and current play a bigger role in this "behaviour". A valid theory is that Xenia tend to pulse at steady, higher pH. Xenia are thought to be autotrophic, meaning that they don't generally require supplemental feeding. What you need to do is to review your tank's parameters once again, checking that pH. Perhaps you are positioning your Xenia near other, more aggressive corals, and they are becoming victims of "allelopathy" (chemical "warfare")? You certainly could experiment with iodine- but do test for anything that you should add. Do pick up a copy of Anthony Calfo's "Book of Coral Propagation" for a thorough review of the care and propagation of Xeniids. Do a little research- you should be successful! Regards, Scott F.>

Xenia is dying Can you please help? I have a 150 reef tank. It's been set up about 2 years. I put in 2 or 3 pieces of xenia more than a year ago. It has grown and speed like wildfire. All of a sudden, they are turning white and shriveling up. Any ideas? <many possible reasons for this but far and away the most common is a low pH. Xenia are notoriously sensitive to low pH. They stop pulsing at 8.3 and really show suffrage under 8.0. A reef aquarium ideally (to me) does not drop below 8.3 at night (low point).> Thanks, Ricky Knapik New Orleans, LA <best regards, Anthony>
Re: xenia
Thank you guys, I changed about fifty percent of my water and put in new carbon and stepped up my skimming. Everything looks great but my xenia still has not opened, I believe they will soon.  <agreed... they are notoriously finicky! But rest assured if they were sick or dying... they would have wiped out like wildfire. You are safe> My question is about skimmers. I have a small ten gallon reef and I can not find out what would work the best for this tank. Every time I think I found a good skimmer I read a horrible review about it.  <quite frankly all skimmers for a tank this size are complete trash. Just marketing wizardry> Could you give me a list of hang on skimmers that would do the ideal job. I have searched high and low but do not and can not afford a real expensive skimmer.  <good things are seldom cheap and cheap things are seldom good. Don't bother buying a good skimmer for this tank. Small weekly water changes would serve you better> Also where would I be able to get that book by Robert Fenner.  <many places including several vendors on the Wet Web Media site. If you go to DI's aquatics (http://www.disaquatics.com) you can get a copy signed by Bob. They have a limited number of hardback copies too.> Thank you so much I appreciate the time, it is invaluable. If ever you are in Minnesota and around Minneapolis and your car breaks down I could repay the favor as I am an auto mechanic. Hehe Dave McCorkell <hope to meet you one day! Best regards, Anthony Calfo>

A Non-Pulsing Xenia Hi there, I bought a White pulsing xenia last week. When I placed it in the tank it looked ok and pulsed like crazy. But at about 3 days I noticed that the middle stalk was rotting so I removed it by cutting the middle portion and left me 2 stalks that are still alive. <Smart move> Since then the my xenia's just stopped pulsing and is turning into a light pink color. Sometimes it pulses but very weak compared to when I first got it. The polyps are open but is thinner than before. What could be the problem? <A whole bunch of possibilities; iodine, low pH, low ORP, current, lighting, or temperature differences/problems.> Thanks <Sorry I could not be move definitive. -Steven Pro>

Xenia rash ??Dear Mr. Fenner, I am writing you again to pick your brain. Question 1: I have a 125G Reef tank which is about 5 months old.  I purchased several "generic" Pulsing Xenia in the beginning of the reef.  I now know why no one else was purchasing them... THEY GROW LIKE WEEDS !!! And worst of all, I can't seem to get anyone to take the excess. Now that being said, I have been thinning out the "Crop" about ever 3 to 4 weeks by removing about half of the stalks.  The "Crop" is not getting any smaller even with the thinning.  I've come to terms with these little tan dancers and don't mind them in the tank, and actually have come to enjoy watching them. Now for the issue.  About 2 weeks ago, I noticed that some of the Xenia had what I refer to as a "rash", the base of the stalk looks fine but moving up, as you approach the branches, there is an area of pitting and blistering of the flesh.  They, are mainly symmetrical in appearance and vary in size from very small to .25" in diameter.  This is the case on about 90% of the Xenia in the Tank, young and old.  The Xenia are in small colonies spread from one end of the tank to the other; so I doubt that this is a case of physical aggression from another Coral body. If you disagree I will send a list of them, just don't want to bother you with an even longer message. I'm concerned because I have read that Xenia do not like, to the extent of fatality, high levels of Calcium.  I recently achieved calcium levels of 475 by increasing the frequency at which I add my 2 part B-ionic solution. I now add it every couple of days.<Hmm, could be the calcium... or some matter that has/is becoming rate-limited by the pulsing corals abundant growth... or possible predation of some sort... but I would not be overly concerned... A die-off is not likely imminent> Question 2: I've recently seen two snail like critter in the tank.  The first one was small and I removed. The second, have not removed and is about .75" long identical from the bottom (outside of glass) as the Astrea snails in color and physical appearance (head, foot, antenna).  But, it doesn't have a SHELL !!  instead it totes around what reminds me of a Medieval shield starting just above the head and ending about 1/2 way down it's back.  As I'm sure you can tell the heart of my question would be: what is it and is it "bad" for the tank ? <Likely not... I would enjoy it, and other life until they prove to be deleterious... the vast majority of such "recruits" are innocuous> Here are the stat's checked monthly; these have been stable for 4 months now, save Calcium: SpecGr = 1.024 pH = 8.4 Alk = 3.43 Ammonia = <.25 <Really? as in zero?> Nitrate = 2.5 Calcium = 480ppm I'll not bother you with the list of Corals and such, since this spans the entirety of the tank. Fish: 3 Green Chromis 2 Kupang Damsels 1 Yellow Tang 1 Cirrhilabrus rubripinnis (Dwarf Parrot Wrasse) I think 1 Cleaner Shrimp 1 Clark's Clown fish w/ Anemone 1 Bicolor Blenny As always, Thank you in advance. John John Boiger <You're certainly welcome. Bob Fenner>

(Not) Sick Xenia Dear Bob, I was surfing the internet looking for discussions on xenia diseases and came across your name. Since your book "Conscientious Marine Aquarist" was the one that kicked off my two year marine aquarium adventure (well, mania!), I thought that I should say hello and thanks! Also, how about a bit of advice... <Salutem dicit. Hello there> I bought a colony of pulsing xenia about a year ago. The colony grows and is expanding. Since it often splits and the partners move away from each other, the colony is not crowded. Every so often, the pulsing heads shrink, often fall off (disappear) and I am left with a fat stem and no heads. However, in a week or two, new heads reappear and I have normal looking colonies. This event starts with one colony and migrates to others-but not 100% of the time. I have digital pictures of the effected colonies if it would help identify the malady. No issues with the rest of the tank inhabitants. I am fairly religious about following your maintenance routine. Any thoughts? Dan Pilipauskas <Yes, not really a malady, but more of a combination "reflex defensive mechanism" for coping with periodic "poor conditions" (lack of "food", current, toxicity...) and device for distribution in space and time. In another way, this is nothing to be really worried about, happens in the wild... Bob Fenner>

Xenia I just added a pulsing xenia to my tank, but it is not pulsing. I have a  100 watt metal halide and two 55 watt PCs. It is a 40 gallon tank. I have  the xenia in medium-heavy current. What should I do? <Perhaps nothing, maybe a few things. I would move the animal out of direct "medium-heavy current" as this is more likely a problem than useful.  I might look into aspects of my water quality (calcium, alkalinity, phosphate, nitrate) and adjust them environmentally if way out of whack. Many pulsing corals respond positively to iodine supplementation. Do you use such? Lastly, have patience. If you have "just added" the specimen, it may well be in "transport shock". Give it a few days to get situated. Bob Fenner>

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