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FAQs about Moorish Idols, Family Zanclidae: Health

Related Articles: Moorish Idols,

Related FAQs: Moorish Idols 1, Moorish Idols 2, & FAQs on: Moorish Idol Identification, Moorish Idol Behavior, Moorish Idol Compatibility, Moorish Idol Selection, Moorish Idol Systems, Moorish Idol Feeding, Moorish Idol Reproduction,

Exophthalmia/Pop-Eye      10/25/18
Hi there,
I wonder if you can help with a question regarding pop-Eye. I acquired a Moorish Idol about 5 months ago, and while he was in quarantine, go through the tank transfer method, he developed a fairly large pop-eye.
<One-sided? Do READ on WWM re... most all unilateral... are due to physical traumas. A Zanclus kept for months is testimony to your good care>
This would get a bit better and then flair up again, but once he settled in the DT, it remained constant. The eye is not cloudy, but it rather looks as if there is a gas bubble behind it.
<That or fluid... yes; does happen; and hard to "remedy">
No other fish in the tank have ever had pop-eye and the Moorish Idol is not being bullied by any other fish. He is healthy looking with no other symptoms, can clearly see the incoming food,(not sure whether with both eyes…), behaves normal and eats well and everything he can get. All water parameters are within a good range, with nitrites sitting around 20. There is no other disease in the DT either.
My question is, should I at some stage treat the fish? Will the pop-eye go eventually away or can it be that it has become a permanent condition after 5 months?
<I would not treat, will not likely go away in any time frame.>
As always, I appreciate your expertise and help,
Kind regards,
Jana Maddock
<Cheers, Bob Fenner>
Re: Exophthalmia/Pop-Eye      10/26/18

Thanks Bob, for the quick reply. Yes, it is unilateral. And it was of course the nitrates (not nitrites) that are at 20!
<Ah yes; assumed>
I’ve always kept the Moorish Idols, the last two in Australia I had for 4 years before we left for South Africa. I collect sponge from the rock pools every now and then…
<Ahh! >
Wishing you a good day further,
Kind regards,
Jana Maddock
<And you Jana. BobF>

Splinter looking spots on Moorish Idol - Black Ich?    6/9/18
Hi there,
I got a Moorish Idol on the 24th of May. They had just arrived at the LFS and I picked the healthiest looking one. He had no marks or injuries on him. I brought him home and took him through the ‘tank transfer method’ in my quarantine tanks, a routine thing I do with all new arrivals. Water parameters were as reasonable as they get with the transfer method, with SG of 1.021.
While going through quarantine, I kept getting sponge from the rock pools, to get him to eat, which was successful. Currently he is eating sponge and brine shrimps. Towards the end of the quarantine he started getting some darkish spots, which looked like Black Ich.
<Mmm; maybe; but these collected areas look more like simply "stress markings to me". Paravortex look larger, more discrete. My old roommate in college, Mike Kent, originally described Paravortex as a fish parasite, so I've retained an interest>
I started treating him with PraziPro, dosing the recommended amount. He has been through a few rounds now and it does not seem to be working.
<It won't if not a worm, Turbellarian>
Initially, the spots looked like Ich, just dark. They were tiny, round - like salt granules, dark and strong in colour. Slowly they started changing. The colour got lighter or more dilute, they grew in size and changed in shape , now looking more like splinters, with the outline being stronger in colour than the inside. (Almost like a ringworm on a human, but in splinter shape and brownish). I have taken some pictures and am hoping you can advise.
<... you could/might sample (see Ed Noga or elsewhere in the field) re sampling, looking under a 'scope; possibly staining>
Every time I treat with PraziPro, he stops eating for a day or so.. so I have done another big water change today from water of the DT, and stopped medicating, as he is starting to get skinny. Otherwise he is in good shape, breathing normal, swimming around and quite alert.
<I would cease treating>
I have tried to look it up on the web, but cannot find anything other than Black Ich, that looks similar. Most images on the net of Black Ich look like the beginning stages of the fish’s spots, round and small.
<... books, not the Net. "Fish Disease, Diagnosis and Treatment">
If it is Black Ich, why is the PraziPro not working? Or is this the natural progression of Black Ich… looking like black dark spots, then growing in size, looking like diluted spinners??
<See above>
With the transfer method and being in a small quarantine tank, the fish has obviously been through stress… could it be environmental?
<Ah yes; a factor definitely>
(Too small tank) The brown marks on his body have not changed in the last few days, not grown in size or numbers (I’ve counted them), nor changed in shape or colour. Could it have come in with the water from the sea or the sponge I collected?
<This too; yes>
Am currently living in Cape Town, so water here quite cold….
Thank you for your help in advance!!
Kind regards,
Jana Maddock
<I would not use wild-collected material; see WWM re Zanclus, feeding. Bob Fenner>

Re: Splinter looking spots on Moorish Idol - Black Ich?      6/10/18
Thanks so much for your prompt feedback… always so appreciated!!
I shall look up the book, thank you!!
<Certainly welcome>
If these are more likely stress marks, would you introduce now to the main tank? Or should we (fish and me:) sweat it out some more?? Both ready to move on...
<I would expedite moving this fish to the main/display myself>
Kind regards,
Jana Maddock
<And you, BobF>

Healthy MI sudden death
I’m writing because I just lost my Moorish idol within hours and I’m wondering if anyone else has had this unique experience and what you think about this:
<Zanclus die... of shock, stress very commonly. See WWM re>
I have a very healthy established saltwater tank (300 gal softie reef) with 40 gal sump and an addtl’ 40 gal refugium. 4” sand bed. I’ve been in SW for 8 years & FW for my life time. (from Florida originally) Oh, and I’m 45 y/o. So, although no expert, very experienced. IMHO.
Okay, having said that, I brought home my first Moorish idol 13 months ago. He has THRIVED. Fat, eats everything I feed him, eats out of my hand. Lives with 2 tangs . red scooters, fairy wrasse, gobies & magnificent Rabbitfish. No problems. Sleeps with my orange shoulder tang (who I've had for 7 years). I recently bought macro algae to make my MI’s diet more exciting. Among the algae I put in the tank and/or my refuge about 1 week ago: bottlebrush, mermaid fan, more Chaeto (have a ton!) and….. macro Eucheuma Spinosum. The latter was in the main tank for approx. a week, not touched. Last night, I get home from work and notice the “orange sized algae” bunch of the Eucheuma is gone. Tiki (my MI) is happily swimming around with an even fatter belly than usual. My husband & I laughed & I saw him at 9pm doing his night routine and I went to bed. I woke up this morning and he was dead.
No parameter changes in my tank, no one else is sick, no illness WHATSOEVER in my tank. I’m heartbroken. Truly. So I am hoping to share this experience & maybe learn as a hobby.
I believe the algae was toxic. I did some research & this is the algae that has controversial (for furry pets) issues… “carrageenan”
<Mmm; could be>
It’s sold commonly in the saltwater aquarium trade, probably most (in fact this is stated) fish don’t like it & it’s a great nitrate/PO4 absorber. But I'm wondering if my pig MI was killed by eating it all at once… and ate a lot. Again, he had NO, zero changes prior in behavior, look or eating habits. Fat and robust as ever.
What do you think about this?
<A theory; could be tested>
☹ I feel horrible about it. Maybe it can be a learning experience for anyone successfully (tentative use of that term) keeping idols.
I would very much appreciate your thoughts & any questions.
<Keep bier in cool, dark places>
Thanks so much for your time, Lisa
<Welcome. Bob Fenner>

Dear Bob
I have a 100-gallon fish only system using canister filtration with ornaments as decoration. All the water parameters are fine, I check them all every week and the system has been running for 3 years now.
I recently purchased a Moorish idol which settled in well in the afternoon of purchase to the extent it was feeding on flake food within a couple of hours! None of the other fish were troubling it.
However, the following morning it was gasping for breath and then later died. I tried a freshwater dip for 10 mins when the fish went on its side but this did not help. I run ozone overnight so it should not be a lack of oxygen. I also have a powerhead rippling the water surface to help with carbon dioxide exchange. A cleaner wrasse also introduced at the same time is fine. I suspect velvet disease.
This has also happened to me before some months ago (exactly the same time frame) with a juvenile emperor angel but I have successfully added butterfly fish, a powder blue, a flame angel and other species without this problem. I have a red saddleback anemonefish but this is clean from disease as are all the other fish.
I now feel I cannot add any more fish until this has been solved as it appears to be certain types of fish that are affected.
Is it Velvet disease? And if so how do I clear it from my system?
I have used copper medication to clear an outbreak of white spot recently so I would have thought this would have cleared the velvet at the same time?
Thoughts at the moment:
1. given the speed of this infection - ie within 12 hours, is it velvet ? or is it a virus ?
2. even though the transfer of the fish appeared fine, velvet can break out following the stress of a transfer so pre treatment with copper would not make any difference
3. I have checked oxygen content - its 6mg/l - exactly the same as my reef aquarium
4. Water changes are 30% per month - could it still be a water quality problem? - Nitrates are at 25 but besides this everything is fine
5. Should I add a uv sterilizer? Is this effective against viruses, probably not?
6. In a separate feeder tank, should I go for miracle mud and macro algae to improve water quality. If I have to treat the main tank with copper, then I could isolate the feeder tank for the duration of the medication
7. Ditto 6 but with live rock
8 I've not lost 1 fish in 2 years in the reef tank so I am leaning towards a water quality problem
I would appreciate your views on the above
I realise some fish require a higher oxygen content than others.
Even at 6mg/l (it could be anywhere between 4 & 6 - difficult to read the test kit) this may not be enough and therefore more water movement could be required to bring oxygen laden water to the fish?
Do Angels and Moorish Idols fit into this category?


Well Ian, there's much to what you state and summat lacking. First, though I too have collected and sold hundreds of Moorish Idols (Zanclus canescens) over the years, I have tried to do my best in being up front regarding their likelihood of surviving under captive conditions. In short, this species aquarium hardiness is dismal. Historically, more than 90% die w/in a week of collection in my experience; given even the best of care.

Even specimens as yours, that was apparently taking dried food, just 'die mysteriously' most of the time. My overall sense is that this species is just very poorly suited for what we can offer it in the way of habitats.
Oh, and you mention a notion that this fish succumbed to Velvet (Amyloodiniumiasis)'¦ Nay! If this were the root cause here, I assure you all your other fishes would have shown symptoms and been just as swiftly dead. Again, I would just scratch the loss up to anomalous death and move on to other, more suitable species'¦ Perhaps the genus Heniochus butterflies'¦ H. acuminatus and H. diphreutes are very similar in appearance (Please see images attached), and FAR more hardy aquarium fare. I do want to comment re your addition of a Cleaner Wrasse here as well. This genus is about as hardy as Zanclus, and I want to discourage its use in most all types of marine systems.
Per your comment re needing to wait on adding any more fishes till this 'mystery disease' is found/cured, I consider that your system is likely all topped off in terms of adding more specimens. Especially with the Powder Blue Surgeon (Acanthurus leucosternon), a very territorial species, I would be hesitant to add more fish life here. To respond directly to your numbered queries:

  1. Neither Velvet nor a virus. Again, take a read in a good marine aquarium book or two re Velvet Disease. Your system is assuredly not infested with this Dinoflagellate. This fish died from 'stress''¦ being 'high strung' if you will.
  1. I am not a big fan of pre-treating or even treating most marine fishes with copper compounds'¦ Two reasons principally; the material is too toxic, and secondly it's hard to keep an effective dose in place. There are reams of materials we could discuss here; suffice it to state that I would look to more efficacious remedies/cures, particularly Quinine compounds (e.g. Chloroquine Phosphate) for treatment of most Protozoan complaints.
  1. 6 mg/l or ppm of Oxygen is fine, near saturation (7-8) as an ideal.
  1. Your nitrates at 25 ppm are a little high'¦ For fish only systems I would strive to keep [NO3] below 20 ppm. One change I would make is to switch out 15% of water twice monthly, or every two weeks, instead of the once monthly water change of 30%.
  1. I would not add an ultraviolet sterilizer here; and these are not directly effective against viruses'¦ As you state you have/use Ozone already. Perhaps I'd add a dryer, or controller to your ozone system'¦ and leave it on, set below 400 microsiemens/cm.

6 & 7. Adding more volume by tying in another sump with Miracle Mud &/or Live Rock is an excellent idea. Adding copper to a main system is NOT! Don't do this'¦ not only does it kill much of the useful biota, microbial and not, in the system, poison the fish life, but the carbonaceous materials (rock, sand) in the tank quickly absorb copper'¦ ALL such treatments need to be done outside the main display, in a separate system sans these hard materials.
8. Considering what you list as fish livestock, your success thus far, I don't think you have a water quality issue. I would be more careful what species you pick, which specimens of these more appropriate types, and for most, carefully quarantine them ahead of placing with your established life. Cheers, Bob Fenner

Moorish Idol - parasite or fungus... Mmm, neither 12/18/11
Hi all, hoping to get some assistance with identifying the disease on my Moorish Idol.
<All righty>
I received the fish on 11/21/2011. (26 days ago). I immediately placed the fish in hypo-salinity at 1.008 Salinity. The fish had no sign of sickness, I just do it as a precaution. Anyway as with most Idol's it took about 5 days to start eating. It is eating with increasing enthusiasm every day. It's gut is starting to fill out nicely. There is however what looked initially like Ich and has developed into something more. It started off with some spots that looked to be under the skin and has increased in size to what is now outside of the skin. The first ones have gotten larger and looks like cauliflower.
<An apt description; this appears to be the environmental/viral condition called Lymphocystis. Please read here re: http://www.wetwebmedia.com/virdisidf.htm
and the linked files above>
The fish has never once rubbed/scratched or shown any sign of stress. I took some pictures tonight (attached) and the larger ones that looked like cauliflower almost looks like a grouping of small eggs. Let me know if you have an idea of what this is so I can appropriately treat.
Picture 3 parasite on the fin seems to be different then all the rest. It looks like cotton.
<This is likely "just environmental"... and the treatment for all is coming... placement in an optimized, stable world... of near seawater strength (concentration) and good nutrition. Bob Fenner>

Re: Moorish Idol - parasite or fungus 12/18/11
Thank you very much. :)
<Certainly welcome and congratulations on your Zanclus... DO please read over what we have archived on this species on WWM, and consider using Spectrum pellets as your staple here... BobF>

Morish Idol, hlth./rdg. 9/29/11
Hi Crew, I got a <Moorish> Idol in my quarantine tank. He is eating great.
new life spectrum pellets, Mysis shrimp, algae.
Pretty much everything I drop in the tank. I am treating my quarantine tank with hyper salinity. I had a outbreak of Ich in my main tank from high nitrates. He in a 55 gallon tank
<Too small>
with a couple of back filters, air stone. The salinity is at 1.009. It looks like he got ich and its impossible right?
<Mmm, could just be mucus-dots... from the low salinity, confinement, other stressors>
The spots seem bigger and they are on the outside of his back fins. They fall off in the morning like Ick and comeback at night. I have few other fish in the tank and nobody shows no sign what so ever.
<Even further weight to the point that this is not Crypt>
The fish himself shows no stress and is eating like a pig. Let me know if you want pictures?
I do a water change every three days to keep the water quality supreme and test it every other day. Jim
<See here re husbandry of this species: http://wetwebmedia.com/FishInd3.htm
and the linked files above. Bob Fenner>

Moorish Idle problems seeing food. 4/24/11
Hi WWM Crew,
We have a 120 gallon tank with a 35 gallon refugium, both with lots of live rock, a Euro-Reef RS-250 Protein Skimmer and Current-USA 48" Outer Orbit HQI/Compact Fluorescent (560 watt: 2-150 watt PowerPaq 10000k HQI Metal Halide; 2-130 watt Dual 460nm/420nm Actinic; 6 white lunar)
Had my Moorish Idle since February 2007 and has always been very healthy.
I feel the success is due to Pablo Tepoot's New Life Spectrum Pellets.
<Pablo keeps this species as well... feeding it exclusively on NLS>
It was just him and a Queen Angel that got to be about 8" in size and some damsels. About a year ago the Moorish Idle started picking on the Queen Angel and we had to choose who would stay. We donated the Queen Angel to The
University of Penn State http://www.advancedaquarist.com/2002/10/aquarium 6 months ago and he is doing very well and we get photos and video all the time from friends at Penn State.
<Typical pickiness, esp. in this small volume>
Since he was alone with just a few damsels we purchased a Powder Blue Tang
<... needs more room>
and a Raccoon Butterfly fish, put them in a 90 gallon quarantine tank and after a week the Butterfly fish didn't make it. After a total of 4 weeks we moved the Tang into the main 120 tank.
Now the Tang has been in the main tank for 3 weeks and he gets along fine with my Moorish Idle <Idol> but in the last couple of days we noticed the Moorish Idle is missing the sinking pellet food when he is trying to catch them.
He now has a cloudy/whitish film on his eyes and you can tell he is stressed by the way he is swimming. Not sure if it is due to parasites, bacteria, or just stress and I don't know what to do about it.
<I suspect some sort of Protozoan from the Acanthurus leucosternon, its addition... I'd be doing a skin scraping, look/see under a few hundred power microscope. See WWM re>
Please help, any recommendations would be appreciated.
North Wales, PA
<Welcome. Bob Fenner, San Diego, CA>

Successful Moorish idol...or not 2/17/08
Dear WetWebMedia. I have a Moorish Idol that I have been keeping alive for 4 months. It is feeding on NewLifeSpectrum pellets, Mysis, brine shrimp and the occasional table shrimp. So far, after 4 months, it has been doing great. Fat and healthy. Here is my problem. It has contracted ich....I have no idea where the ich came from as I have not added any recent livestock, except a Xenia colony from a LFS. Is it possible that the ich came with the
water at the LFS?
<Mmm, yes, possible... But likely you may have "just" a resident infestation (quite common), that is expressing itself given sufficient "stress"/imbalance of some sort>
Anyway, no use figuring out where it came from...fact is it is here. I do have 2 Lysmata amboinensis and a neon goby. Also a cleaner wrasse that is eating everything the Moorish idol is eating. This wrasse has been with me for 7 months. Lucky i guess..bought it when it was a juvenile. Has attained full adult colouration and is eating prepared food. The idol does not seem to be interested in the cleaning services though. It is still eating like a pig and seems unaffected by the ich. I'm tempted to run copper in a QT, but I do not want to risk it.
<Mmm, good>
It took me awhile to get the idol eating everything. If it reacts badly to the copper and loses its appetite for good, I will kick myself for it. Do you think with continued good nutrition and water changes, the idol will gain "immunity"?
<Is possible... I would give the new college try of Garlic (fresh or a commercial paste added to food) a go as well>
I have a separate 3ft tank with Clowns, Coral beauty, Yellow wrasse and assorted Cardinals. That tank came down with ich few months ago,
<Oh, then this is very likely where the "new" ich came from. Please read here: http://wetwebmedia.com/parasittkfaq2.htm>
but I just ignored it and fed more than usual and did more water changes.
The fish after 2 months, are spotless and in perfect health, even though ich is still present. I don't know if it is immunity, or what, but it worked and ich did not bother them for 2 months. I am sure ich is still there, but it just does not bother them because of immunity? You might want to enlighten me here. I am hoping to repeat this with my MI. It is eating
well and unaffected by the ich. I really do not want to treat it as i am afraid the stress from copper and hypo and what not will stop it from feeding. I am also afraid it might lose its appetite for good. What do you think? Should I just continue feeding it well and let it fight the ich off by itself, just like my other fishes in my 3ft tank?
<Yes... I would>
I am no expert, so whatever you say, I will do. But my MI is feeding like a champ, and really don't want to risk it.
<Try Spectrums "TherA" product... has garlic...>
It just bothers me seeing it covered in spots. I felt the same way too when my 3 footer was invaded by ich. Was just too busy to treat it as i had work and was busy with my new born. Somehow, the fishes in the 3 footer manage
to battle off the ich and has been ich free ever since. NOT EVEN ONE SPOT.
I am very sure they are still infected, just not at catastrophic levels.
<You are correct>
Please advice. As I have said, I don't wanna risk getting my MI to stop feeding due to the stress that copper might induce. Although copper if administered properly can cure it, I just simply don't want to risk it.
Besides, even if i cure the MI, I still have to cure the other fishes and let the tank run fallow.
<This is also correct>
So far everything is still normal. Don't want to fix an unbroken pipe, in this case, the pipe is slightly broken, but is it in need of fixing? Or could the slightly broken pipe do without fixing, and live with the slight break?
<Or maybe move to a place sans pipes?>
Sorry for the lengthy and mostly repetitive mail. I hope you understand that having found a MI like this on my first try, I am very protective and paranoid.
<And you, Bob Fenner>

Moorish Idol Hi, Bob: Greetings from your most loyal fan in Hong Kong again ! ( I read your column almost every day !!!) <About as often as I write it!> However, I don't find anything much written in your Moorish Idol section. <Not yet... really don't want to encourage people to try this tang relative...> While most people complain Moorish Idols don't feed, mine always have a hearty appetite --he eats anything from pellets to frozen brine shrimps to worms to finely chopped clams. I 've had him for more than a month now. Recently , I have noticed that his body has very fine dark colored spots around his body, particularly on the yellow parts of his body. Thus, he looks dirty. Yesterday, I decided to move him to my hospital tank and put some low levels of CopperSafe. He stopped eating for 1 day, and the next day his appetite returned heartier than ever. However, spots on his body seemed to be the same. He remains a very active swimmer . Kindly advise what disease this is, and if I am doing the right thing. More Power ! <If you have had this specimen for a month and it is eating well, you are definitely "doing the right things"... I consider that the darkening, markings might well be transitory... and wouldn't worry about them> On a separate matter, can you recommend some good sites which discuss more extensively about groupers? <Wish I could. If you find such, please send them along to place as links on the appropriate (serranid) sections of WetWebMedia.com> Warm Regards. Richard Fan <Be chatting. Bob Fenner>

Bacterial or Parasite Infection? Sad to say, my Idol came down with something and can't figure it out. I'm sending a pic. I treated him with Rally and Melafix, it started as a darkish patch and then the skin peeled away leaving a open sore. Bacterial or Parasite infection? Is it contagious? <clearly not parasitic... bacterial or viral. The above treatments were way too mild. This fish needs serious and strong antibiotics in a hospital tank. If you do not have access to vet prescribed drugs, use a product like Jungle brand "Fungus Eliminator" at double strength for five days with daily water changes and good feeding. Else, find another Furazolidone/Nitrofurazone combination. You should see stabilization or improvement within 3-5 days or another antibiotic may be necessary. Best regards, Anthony> Thanks! Gary Gregory Medford, Oregon

Marine dips/baths, Zanclus Robert Fenner, I just realized that you're the author of what has been my bible over the past few months. Duh... That was where I found out about the Methylene blue. I have another question for you. What can I do as far as "decontaminating" a fish that is too large to quarantine in my 10g? <An extended dip/bath... you may benefit from reading through the articles and associated FAQs files here: http://www.wetwebmedia.com/dips_baths.htm the blue items at top are links> (other than setting up another quarantine tank). My local aquarium is breaking down an exhibit that has had a Moorish idol in it happily for over a year and I told them I would take it since I have plenty of room in my tank. But I do not think it would be very happy sitting in my 10 g for 2-3 weeks. <I agree with you. Best to give it a dip/bath and place it in the main/display tank ASAP... slightly reduced spg, matched pH... perhaps a little Formalin and/or copper sulphate> Do you have any ideas? Oh and I treated the other fishes (in quarantine) with malachite green/Formalin and all spots seem to be gone. thank you again, Jessa <You are welcome my friend. Bob Fenner>

Re: Marine dip/baths cont. Bob Fenner, Yep, I read that one and came to the conclusion that the Methylene blue/FW dip would be best, but it doesn't seem like something I could do as an extended dip, I just really don't want to mess this up. This is really a magnificent fish. I what I am asking you is what would you do? I trust your opinion. Jessa <1-2 minute dip/bath... then into the main tank. Bob Fenner>

- Moorish Idol Popeye - Hey guys, I lost your reply about my Idol but thought I better give you an update. I wrote to you on Jan 18 and stated that my Idol had severe Popeye in both eyes. He hadn't eaten in about 2 weeks at the time. Just this week he started eating again and is eating vigorously. One eye is still terrible and he appears to be blind in it. <Bummer.> The other eye is pretty good now but he can't seem to pinpoint his food very well. He tries hard though and eventually gets it. Maracyn didn't seem to work and neither did Furan-2. <The causes of Popeye aren't always bacterial... and in those cases Maracyn and Furan compounds won't do anything to help.> Prayer was the best option. PS: you said that they are best viewed in the wild--I agree. My wife and I both have dove the Kohala and Kona Coasts of Hawai'i and they are magnificent. Moorish Idol lovers, don't give up. <I'm sorry, but I just don't agree... when 99% of these fish that are caught for use as pet fish, die... something ain't right. Hope things work out for you and your Moorish Idol, but having dived with them myself, I just can't encourage anyone to keep them. Cheers, J -- >

- Sick Moorish Idol - I have a Moorish idol who has Popeye (BOTH eyes protruding badly) and I have him quarantined in a 29 gallon tank giving him Maracyn 2 as prescribed and monitoring the water parameters rigorously. Prior to this he was a voracious eater; seaweed, plankton, Formula 2, Cyclop-eeze--he wasn't picky after the initial no-eating stage. Question: How long can a fish like this survive without eating since he hasn't eaten in about a week? <Probably not much more than two weeks... in the wild these fish are fat and eat constantly. If yours wasn't holding its weight, then your mileage will vary.> His eyes are marginally better but he is relatively blind since the extreme protrusion. Is he possibly beyond the point of no return? <I hate to say it but it's very possible.> I know from my African Cichlids that a brooding female may not eat for a solid month and do just fine but Mr. Zanclus is a pretty thin profiled fish even when healthy. <If this fish was thin to begin with, then the outlook isn't good.> Beautiful fish, hate to lose, please advise. <You need to see these in the wild... rarely see one that isn't eating. If you can provide a constant source of algae, other foods, you stand a better chance of keeping these. Very challenging fish to have for any period of time. I wish I had better news for you... am hoping that things improve. Cheers, J -- >

Moorish Idol Swelling of the Mouth 8/16/05 All, <One> Let me first say thanks for all the extremely valuable information you have provided me over the past year. I never would have attempted saltwater keeping if it wasn't for the information provided at your site. <Welcome> My problem is this: I have a 150 gal FOWLR tank with the following inhabitants: 1 Moorish Idol 1 Cinnamon Clown 1 Yellow Tang 1 Hippo Tang 1 Diamond Watchman Goby 1 Flame Hawkfish 1 Fire Goby 1 6 Line Wrasse 1 Cleaner Shrimp 1 Pygmy Angel Several Mushroom corals Several Leather Corals 150lbs. of live rock Lighting is provided by 4 96W compact fluorescent lamps (2 actinic and 2 10000K) The water parameters are: PH 8.2 Ammonia 0 Nitrites 0 Nitrates 20 S.G. 1.022 Temp 78 The problem I am having is twofold. First, My Moorish Idol has stopped eating. <Common> It came with the tank I purchased 14 months ago. I would not otherwise own one as I know how they acquire these specimens. <Mmm, actually... have collected Zanclus... in Hawai'i, Mexico... they're caught with hand and fence nets, the same as most tropical marine fishes> The previous owners said it has always eaten great and I have not had any problems with it either, until now. It seems to have some sort of swelling in its mouth. <Not good> Its breathing is faster that usual. He doesn't have any signs of trauma anywhere. I usually alternate feeding him Mysis shrimp and Formula Two mixed together and some homemade fish food I purchase at my LFS once a day. My question is: How can I tell what is wrong with him and what can I do to treat it. <... not easily done... if you're referring to root cause/s> All the other inhabitants of the tank are doing fine, with the exception of my star polyps, which brings me to my second question. A couple of months ago, they began retreating and they have all but vanished. What was once a very large carpet of polyps is now only a few individual polyps. My water parameters have stayed constant the entire time I have owned the tank. I do a 35% water change every 3 weeks. It seems as if algae has been growing over the polyps, cutting them off. I am not sure, but I think I have high levels of Phosphate in the water, but do not know for sure because I do not own a test for it. <You might invest...> Even with regular water changes, the algae seems to be taking over. I used to feed twice a day, then cut back because my nitrates increased. I am at a loss as to why my polyps and Idol have both "gotten ill" within a couple of months of each other. Thanks John Banks <Very likely all related... I would read here: http://www.wetwebmedia.com/po4faqs.htm and on to the files on Algae, their control, and look into/purchase some Spectrum pelleted foods (about the only thing I've seen Idols eat universally), and improving your water quality period... and quickly. Adding a live sump, some new live rock... Bob Fenner>

Re: Moorish Idol Swelling of the Mouth 8/17/05 I forgot to mention that I have an Amiracle skimmer in an Amiracle sump with bio-balls as the biological filtration. I also run an Eheim filter with carbon and ceramic filter media. Thanks <I would get rid of the bio-balls, likely trade in the canister filter... More troubles in the way of water quality... Please see WWM re. BobF>

Moorish Idol Survivability (Poor), feeding a big Ritteri anemone - 10/12/05 Hello All, <<Greetings>> I want to try to get two topics for the price of one. <Alrighty>> All is well nothing sick, just general questions of curiosity. <<ok>> The first is my Moorish Idol. <<Mmm...>> I have had him for about 6 months. When I bought him he was a little under weight and had a cut on him. He is doing awesome. <<For now maybe.>> His color is vibrant, cut has been gone for months. He is about 6-8" so he is good size. <<agreed>> He is eating, Seaweed Selects, frozen mysis, live worms, alga wafers, you name it he eats it. <<Sadly, this usually still proves to be insufficient with these fishes.>> He is the first one in line when I feed, also eats flakes. When I first got him all he would eat is wafers. My question is, I was reading a article that stated no matter how good they do, they will perish. Something about a enzyme they eat in the wild, that we can not produce in an aquarium. Is this true? <<Not familiar with the "enzyme" theory, though it does go with what I've heard/read as far as not being able to accurately reproduce the dietary requirements for long-term health/vigor. I've been in this hobby a long time and tried; albeit unsuccessfully, to keep Zanclidae more than once (has been more than 10 years since my last attempt). They all would eat, seem to be healthy...but then one day, two or ten months down the road, you come home or get up to find it dead in the tank for no "apparent" reason. All you have to do is look around you...how many Moorish Idols do you see on display, or in other hobbyists tanks (long-term)? It's not because they don't have appeal/are not available to the trade. I wish you luck, but this is another specie best left in the sea.>> Secondly, about 2 months ago I purchased a Heteractis magnifica. It has a extremely deep, colorful purple base. Never have seen one like this. It is about 24" wide. It is huge! <<And will likely get bigger.>><Not as far as RMF is aware> I have read conflicting articles on FAQ's and others. Some say to not feed it at all, let the clowns do it (They do but not much). <<Mmm, nope...needs to be fed.>> Some say to feed it chopped silversides 1-2 times per week. <<Not the best diet...do provide some variety...chopped table shrimp/fish.>> Others say once a day. <<Maybe more like 2-3 times a week.>> Due to the anemone being so large, I have been feeding it chopped silversides and shrimp daily. It seems to be doing well. <<This might be fine (small portions). Let the anemone's health/appetite be your guide.>> I just am trying to be pro active and not reactive. <<Does pay dividends.>> Thank you for your valuable time. <<Happy to assist, EricR>>

Moorish Idol Mortality - 03/15/06 Hello esteemed purveyors of sound aquatic advice, <<Mmm, one can hope...Howdy!>> First of all I would like to thank you for your wonderful site. It has helped me tremendously, which is why I feel bad questioning certain info on your site. <<No need to feel bad my friend, intelligent debate is always welcome...question away!>> I was wondering how you can be so certain the Moorish Idols who died in captivity after eating well for over a year died of starvation or nutrient deficiency. <<Hmm, well...speaking only for myself here...I don't consider it a "certainty" as much a "theory". Lacking any real documented scientific evidence (results of post-mortem examination <necropsy>/any real knowledge of this fish's nutritional requirements), and considering the seemingly large proportion of fish that perish just as you have described, lack of "proper/necessary" nutrition seems completely viable. Also, rumblings/rumors of successes with this fish by utilizing/getting them to feed upon the 'New Life Spectrum' line of foods lends credence to this theory.>> Is it possible they ate something they shouldn't have (poisoned) or even lost the ability to digest food. <<Indeed...the careless use of an antibiotic can have just such an effect, but I doubt this is the cause for large scale losses. I still think a missing nutrient better explains the problem overall.>> Tangs (a relative) have certain things in their stomach to aid in digestion and when it's lost due to illness or distress, they need another tang to seed the tang with the stomach fauna they need. Could this be the case for Moorish Idols? <<It could...from time to time...>> The possibilities are endless. <<Mmm, maybe>> I really value all your assistance and don't wish to seem ungrateful by questioning your genius. <<Hardly a genius here, but thanks <grin>...and you don't seem "ungrateful" at all...these are good points for consideration/examination.>> I just thought you guys might be painting yourselves into a corner by making starvation the only possibility. <<I don't think any of us have made it the "only possibility," but until better data becomes available to the contrary, I do feel it is the best explanation.>> Sincerely, Jose Saldana <<Be chatting my friend, EricR>> p.s. I wrote you a long time ago about a Moorish Idol my wife bought me that died about ten minutes after I got home from work. I've since bought a 2.5 " one that's been alive for about a month. I don't doubt your statistics regarding mortality, so I'm keeping my fingers crossed and trying hard to make his life worth living. Thanks again for all your help in the past and I'm sure, the future. <<Ah, I truly love these fish...I wish you success! Do look in to the 'Spectrum' line of fish foods...and please keep me posted on the fish's progress. EricR>>

Moorish Idol Mortality II - 03/16/06 EricR, <<Jose>> I should have mentioned I took your (WWM) advice about the Spectrum food the day after I purchased my Idol. <<Great!>> Unfortunately, I have yet to see him eat anything other than coralline algae and the various types of macro algae I have in my tank. He has regular bowel movements and seems thick. I'll keep trying the Spectrum. <<Ah yes, very important to train it to eat this/other prepared food.>> Thanks Again <<Welcome, EricR>>

Moorish Idol Death - 02/17/05 Hi, <<Hello>> I would like to express my appreciation for all that this site has to offer for aquarists of all experience levels. <<Thank you for this.>> I have a question about a mysterious death of a fish that I had for about a year. Up until last night, I had one of the most beautiful fish I have ever seen, it was a 7" Moorish Idol. <<Ooh...I love these fish...>> Now before I get reprimanded for buying a fish like this, <<Hee! I see you've gotten to know us. Actually, this fish has "moved up the ladder" a small bit with the introduction of some commercially available prepared foods (Spectrum) that reportedly are helping with providing the nutrition essential to this fish. Now don't take this as an endorsement for folks to run out and buy Moorish Idols for their tanks! I still believe this fish is best left alone/in the ocean by most hobbyists.>> I would like to say that I bought it from the most reputable dealer in my area (I had to drive 2 hours each way with this thing in a plastic a little bigger than a basketball), it was fat, it had the most gorgeous coloration I have ever seen on one of these fish, it had been in my tank (6 ft 135 gall....a little small but an upgrade is in the works.) for a year and was not skittish or stressed, eating like a pig, and not being bothered by anyone, he was the king and the centerpiece of the tank. <<I share your enthusiasm, truly magnificent fish. I had the opportunity to see these fish in their natural element while diving on the Big Island last fall...captivating (as was so many things/everything there <grin>).>> Yesterday morning I fed the fish and he ate his usual amount and had no signs of disease or damage. That night I came down to feed the tank, I do two feedings a day and Nori in between, and he was dead on the bottom, no signs of damage and he did not have any apparent disease on the outside or internal parasites and all of the other fish are doing fine. What could have happened? <<Though you don't say what you were feeding this fish, though you say this fish was feeding well, it likely died of long-term malnutrition/some dietary deficiency. This is thought to be a common demise...so much we don't know about this specie yet. But as mentioned earlier, there has been some promise shown when the fish are fed/will accept the New Line Spectrum brand of prepared foods.>> I immediately checked the levels and they are perfect. <<Likely this wasn't a water quality issue.>> I know that this fish has somewhat of a dismal survival record but he was always the fish that I never had to worry about, probably the easiest fish I have ever had. The tank looks so empty now. Any help that you could give me is appreciated. Regards, Dave <<Like I said, I'm hesitant to recommend this fish to anyone but if you do try again, request your LFS obtain its stock from a Hawaiian supplier, and give the Spectrum food a go. Regards, EricR>>

Moorish Idol Death - 02/21/06 Hi, <<Hello Dave>> Thank you so much for your help. <<My pleasure>> I had been feeding him, Formula 1, 2, Nori soaked in Zoe, Mysis shrimp, and another frozen cube, I'm not sure who makes it but its a combination of brine shrimp and other meaty foods for carnivores. <<I see...a good mix...still may not have been enough. No way to know without a necropsy.>> Also, I used Formula 2 and Spirulina in the flake form as well as formula 1 pellets. Along with the Zoe I also used garlic extreme by Kent as a supplement. <<Mmm...of dubious utility...in my opinion. I consider Selcon or Selco to be a much more worthwhile product.>> I also checked out the Spectrum foods on their website and I was wondering what kind of Spectrum I should be using for this fish? <<The marine and color formulas>> Since I had a good deal of luck with my first Idol I will definitely give another try, they are so beautiful and they almost become like the family dog, it would come to the glass every time I approached the tank and would eat the Nori right out of my hand. Do you think that it is better to find a bigger sized Idol or should the usual 3-4 inch rule apply? <<Stick with the 3-4 inch specimen.>> Thanks for all of your help. --Dave <<Welcome Dave, EricR>>

Happy Balance Of Ich In The Reef Tank?? - 02/22/07 Hi crew, <<Hello Jana>> Could someone please advice me on the following? <<I'll give it a shot>> I have a 430 litre reef tank that has been infested with ich for some time now. <<Mmm, indeed...these protozoan pests are present in most all aquaria, to some extent>> My inhabitants are 2 medium Moorish idols, <<Difficult to keep>> 1 yellow tang, 1 juvenile emperor angel, 1 milky way cardinal <<...? I'm going to go out on a limb and guess this last here is a Banggai Cardinal>> and the latest edition was a redline cleaner shrimp. Except for the cleaner all fish have been treated with copper twice already for 14 days and the main tank has run fallow for 36 days (1st time) and 30 days at 28 degrees second time round. <<Hmm...some would say a minimum of six weeks fallow is best>> The yellow tang did not take well to the Cupramine but came right after being introduced back into the main tank. <<Ah, yes...hopefully the bacteria in the fish's gut has not been too severely malaffected>> Both times when I reintroduced the fish the ich came back. <<A longer fallow period would seem to be called for...though this is not foolproof, and even when successful is only temporary as the protozoan is so easily reintroduced>> Very subtle on the 2 Moorish idols and a few spots on the angelfish. Yellow tang and cardinal are completely clean. <<No...just not manifested as "spots">> The newly introduced cleaner shrimp does not seem too interested on the job. <<Sometimes happens, but these "bio-controls" can be very helpful where this pest is concerned. I would obtain one or two more>> All fish seem happy and healthy (other then the few spots), eat well and look good. <<Not uncommon at all. If water chemistry is kept optimal, the fish are not overly stressed and are well fed with an appropriate diet (some added vitamin supplements would be a good idea), there's a good chance they can fight-off/keep the infection from becoming problematic>> I've been reading your website for months now (best of all sites!!!) and find it very interesting. <<Is good to know>> The ich in my tank however seems to be persistent. <<Oh yes!>> I have read a couple of frequently asked questions where you guys talk about reducing the virulence of the problem. <<A healthy, well balanced system is key>> Bob advised once to 'give it a good two months of running the tank fallow to be more or less (90 some %) sure of reduced virulence' in an extreme ich infested tank. <<Good advice from a man who's seen much more than most re this hobby>> I've also read of tanks with an existing balance of ich and fish. <<Yep...as already stated...is present in most everyone's aquaria>> So my questions are: What are the chances of actually having an ich-free tank once there has been an infestation? <<Ich 'free?' Is possible, though usually short-lived>> From what I understand, even after months there can still be a few hardy ones left. And if ich exists in the tank but is under control, how does it stay under control and does not break out every now and then? <<When I first ventured in to the marine hobby several decades ago the saying regarding ich infections was "not if, but when"...and this still holds true today. In my opinion, your best defense/weapon against ich...aside form proper quarantine/prophylactic treatment...is to maintain optimum water conditions and stock wisely (don't overload the tank, house incompatible species, etc.)>> Every time one adds a new fish, the new guy on the block picks it up, right?? <<Usually as a symptom of stress from being the "new kid in school," yes>> Other then what I've already been doing, can you suggest anything else that there is left to combat ich. I seem to have a mild but constant infestation. <<If the infection is not worsening I would be inclined at this point to keep a close eye on things and let the fishes immune response deal with the protozoa...oh yeah, and add a couple more cleaner shrimp...>> Thanks for all your wonderful advice, Jana <<Quite welcome...happy to assist. Eric Russell>>

Re: Happy Balance Of Ich In The Reef Tank?? - 02/23/07 Thanks Eric for your speedy reply and advice. <<Quite welcome Jana>> I think I'll do just that, instead of moving fish back and forth in and out of quarantine, I will see how it all goes, seeing that fish seem happy. <<Ah yes...the "fuss" can sometimes do more harm than good>> Oh, and will get another cleaner shrimp or two (not cheap these little creatures).. <<Indeed...if you're in the UK, I remember the prices as quite dear for these little crustaceans, though camel shrimp were quite cheap by comparison...if you are "down under" I expect prices to be even more inflated>> My Moorish idols by the way are awesome. <<Much in agreement...I am particularly enamored by these fish and would love to have a tank-full myself>> I heard that they are difficult to keep but I got them fairly small and have them on the Spectrum food. <<EXCELLENT! Of the few successes I have heard about concerning these fish, New Life Spectrum foods have played a key role>> In between I get them sponges and other algae from the ocean (live by the beach, Australia). <<(Ah, mystery solved) Do be cautious of introducing pathogens/parasites>> They eat like pigs. <<Very good to hear>> Anyway, still wanted to know what you think of how many fish one could keep in a 430-litre tank without overcrowding? <<Depends on the fish Jana...what do you have in mind?>> Wanted to add a majestic angel still and may be a pair of maroons... Too much? <<Considering the Moorish Idols and the already established Emperor Angel, yes. If you wish to keep the Z. cornutus happy and healthy I suggest you look to a specimen or two of smaller and more "peaceful" species>> Thanks again for your advice, Jana <<Always welcome. Eric Russell>>

Moorish Idol, swollen eyes, no useful info. - 12/13/07 Hi, thank goodness for people such as yourselves with web sites like this one! <Glad to share> I have just come home to find the Moorish Idol with large swollen eyes, one is slightly pinky red around the inner edge. He had been feeding well, and this is the first time he has shown any signs of illness. <... how long have you had this fish? What re the system? Tankmates, foods, feeding...?> I'm not sure what to do, or if to put anything into the tank medication wise ( there are crabs and shrimp in there ) so I'm limited to what I can put in ( I think!? ) <...?> Hope you can help, any advice would be welcome. All advice given in the past by you guys has been great, and always worked, hope you can come through for me again. Amanda <Need data to develop a first approximation... BobF>

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