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FAQs about Moorish Idols, Family Zanclidae: Stocking/Selection

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 Systems, Moorish Idol Feeding, Moorish Idol Health, Moorish Idol Reproduction,


Moorish Idol Selection      2/7/17
Hi Bob and Crew,
I am planning on acquiring a Moorish Idol for my 400g display. I am aware of the challenges involved with this fish and am willing to face the challenge. I just want to make sure I'm doing everything I can to increase the chance of success in captivity. I am pretty strict about quarantining any new fish (had a disaster with marine velvet a while back) and am hoping I can successfully get an idol through QT. My QT tank is a 55g bare-bottom with PVC hiding places, two powerheads, HOB filter, HOB skimmer, and an air driven sponge filter. I normally follow a QT routine which involves
prophylactic treatment with Chloroquine phosphate and PraziPro, but I'm not sure if MIs are known to have any particular sensitivities to either of these medications (like certain wrasses do).
<Not as sensitive as Labrids>
My plan is to try to keep him in QT for at least 30 days and try to get him fat off of live clams, live brine shrimp (in Selcon), frozen angel food w/ sponges, Nori, and NLS pellets. Does that sound like a good plan?
<Mmm; yes>
I have some concerns about aggression from my trio of 3-4" yellow tangs once he's in the display. The only other fish in there right now are a 5" regal angel, 6" powder blue tang, and two ocellaris clowns. I know idols are dominant once they get established but I'm a little worried about him being able to get acclimated and eating well initially. I've been
considering going with a larger specimen in order to help with surviving QT (thinking larger fat stores) and to help with the initial aggression. Is this a valid line of thinking or will a larger specimen possibly make aggression worse?
<I would seek a "full", well-rounded specimen of moderate size (about the body of the Yellow Tangs)>
Has there been greater success with smaller specimens (easier to wean onto a captive diet)?
<Medium size are best... small ones die easily for starving, stress; large ones don't adapt>
Thanks for your advice!
<Glad to share with you. Oh! Do look for the Coral Magazine issue (likely through their website) that dealt w/ Zanclus in captivity... several years back. Bob Fenner>
Re: Moorish Idol Selection      2/7/17

Thank you so much for that amazingly quick response! Your advice is greatly appreciated. Hopefully I'll be able to report back a couple years down the road with a rare success story.
<I look forward to it Eric. BobF>

SW stkg.  7/3/2011
Hi there Bob and Crew, I was thinking of purchasing a Moorish Idol, and a Golden Butterfly. Comp.
The MI and GB our both eating everything including pellets. I was wondering if they would get along?
<Not a good choice. Better to have two Chaetodon larvatus>
I also have candy striped shrimp, crabs , and snails. Do you think they would eat my clean up crew?
<Not likely, no>
They will be going to 180 gall tank for year or two, then I am planning on buying a 300 gall tank. Thanks, Jim from Idaho
<I'd hold off on trying a Zanclus... really, most don't "make it". Bob Fenner>

Moorish Idols Mr. Fenner, <"Jim, I'm just a doctor". Sorry am an old Star Trek fan> Just wanted to post something regarding a letter in the FAQ on Moorish Idols. One of your other readers mentioned that his had small, dark spots on it's body, particularly in the areas that are yellow. Mine also had those spots. Looked like a flatworm infection or something like that. But he lived for nearly a year (till an unfortunate A/C accident in July sent the tank temp to 95) <Smoking> with those spots, and they never got any worse or seemed to bother him. Never even saw him scratching. Not that I am trying to encourage anyone to buy this delicate animal. I myself have pretty much given up on Idols. In ten years of trying (roughly 9 or 10 fish), two lived and thrived, while the others all perished inside of three weeks. If you can get a healthy, unstressed, undamaged specimen, they make beautiful pets. But the odds are not good, in my experience. Just wanted to supply an answer, since I do have some experience with these. <Agreed entirely. Thank you for your input. Will post for others edification. Bob Fenner> Sincerely, Jim Jensen

"The Undiscovered Country"  (Keeping Difficult Animals) ScottF: <Hi there again, Steve!> I strongly agree with your advice not to buy Moorish Idols. Just because one has been "fine" in someone's tank for many months does not mean it is actually in good health. <Yep! And, unfortunately, as hobbyists we are often lulled into believing that because someone has managed to keep a difficult fish like this alive for some time, they have "mastered" its care where all other hobbyists and many public aquariums have failed. We are often on the "cutting edge" of husbandry with marine animals, but we need to really study the requirements of such animals before we experiment with them...Keeping a fish that lives 10-20 years in the wild for 1, 2, or even 5 years does not constitute success, IMO> Fish often seem "fine" up to the moment they die. A friend of mine who was bragging about how healthy his was and how much it was eating found it dead one morning after about six months. Probably starved slowly. <An all too common experience...> All tests normal and all other fish fine in this long-established large tank. I'm  beginning to feel the same way about Chelmon rostratus personally. I had a 5" one that was thriving--eating a large variety of foods vigorously and active--for several months. One morning he was leaning dead against a rock. Had responded normally and eaten well the night before. <Yeah...this is not an uncommon experience with these fishes. There must be some sort of dietary issue that we are not solving, even with the best captive diets, and with excellent water conditions. Some fishes simply do not adapt to captive life. We need to really research the academic studies on such animals, and perhaps we can glean more about what they need to thrive in captivity...With the vast knowledge out there on the internet, and the many discussion boards out there, many of these mysteries can be solved> All other fish remain fine and all tests normal.  Steve Allen. <Well, Steve- I'm glad that you share this philosophy! As hobbyists, we have a responsibility to the animals that we keep, and to the wild reefs. It's important to continue to push the "state of the art" in aquariology, but we need to do it in a highly disciplined, controlled manner, with a complete understanding of the ecology of the animal in question. Most important, never forget to share your successes (and failures, for that matter!) with your fellow hobbyists. Together, maybe we can unlock some of the mysteries that may make it possible to keep these challenging animals for their natural life spans. And THAT is success! Here's to the future, the "Undiscovered Country" (Yikes! I've been watching too many "Star Trek" movies...!) Regards, Scott F>

Moorish Idol   I have a 7 month old 75 gallon tank, 80 pounds of sand,  40 pounds of live rock, a skimmer, filter, UV sterilizer, 6-line wrasse, Purple Tang, Kole Tang, 2 Percula Clownfish and 1 Banggai Cardinal fish. I was wanting to try a Moorish Idol as my LFS gets them in every week and they said the odd one doesn't eat.  Could I try this in the near Future? Thanks From Canada, Akira <The odd one lives... I would wager more than 99% are dead w/in a month of collection. Good luck to you. Bob Fenner>

Moorish Idol/Moving To Larger Aquarium 3/26/04 Good Morning Crew from PA  The move to the larger aquarium has been accomplished and was uneventful.  All the original livestock has settled in and seem to be enjoying the new digs.  My yellow tang was a little stressed for a few days but has settled in doing fine.  ONCE AGAIN, I CANNOT THANK ALL OF YOU ENOUGH. <Glad you have benefited from WWM!> This was a big step for us.  When all is well you hate to disturb things but to make improvements sometimes you have too.  This has been one of the most wonderful projects my husband and I have done together, with your help it was a year+ of learning and tremendous pleasure.  To have these creatures in our home is truly special.  Nothing like freshwater hobby (have had them for some 30+ years). Do have a question!  Have always been attracted to the Moorish Idol.  Have not been able to find out much about them.  I know they are finicky to keep but with some effort CAN they be kept healthy in captivity?  If it is only a matter of some effort I wouldn't mind but if they stressed or unable to be fed that is a different matter. If it is within reason I would like to try! Your advise please fellows. Regards Ceil Wagaman <Moorish Idols are very difficult, but it really isn't just a matter of effort.  Many won't eat, and even those that do still fail to thrive.  Getting a healthy specimen is extremely critical to success.  Specimens from Hawaii have the best chance.  Specimens from elsewhere should be totally avoided.  It takes a special LFS to be able to trust that you are truly getting a Hawaiian fish.  Diet must be varied but be heavy in marine algae.  Large amounts of live algae on substrate is beneficial if not critical for success.  Aggression by tankmates will almost certainly lead to death.  Overall, any attempt to keep this beautiful fish should be well researched and very thoughtfully carried out.  Best Regards!  Adam>

Re: Stocking An Angel, now Snowflake Moray beh., and Moorish Idol sel.   8/21/07 Thanks, I think on your advice I'll stick with the Hippo... Bob, I obviously thoroughly read your FAQ's and information on Snowflake Moray's... And I've had mine for almost a year now... He's a little over 2ft. In the past 3 weeks, he's started 'wigging out' and jumping. My water level is a good four inches below the top of the tank, I have egg crating over each of my three top openings weighed down with 2x4's that support my PC lighting. <Good> In both instances there was food present (the kind he'd be after... i.e not flake or pellet). Instance one, he went for a piece of scallop and instead decided to wrestle with the feeding stick... After a few seconds he just flew to one side of the tank and back and then out of the tank, up the wall... Luckily falling back into the tank. The second instance was just last night where I dropped a few tank thawed krill into the tank. My Harlequin Tuskfish went after the same piece the Snowflake was after... The eggcrating was on (secure I thought) and when he jumped he managed to wedge himself in between the egg crating and the glass top. A few squirms and he was up n over and onto the floor. I scooped him into my largest net and placed him back in the tank and he quietly returned to his hole. <Happens... this is not atypical behavior for Echidna nebulosa in captivity> I'm a little worried that he is so peaceful and well behaved, but if I add perhaps a Trigger or Angel... That they may compete for his feeding stick dinner, thus repeat jumpings. I know that they are notorious escape artists... But is it common for them to scare like this? <Yes and yes> On a side note, I'm worried that my favorite fish retailer has disappointed me this past weekend. 4 x 10" Moorish Idols for sale for $110/each. Listed as a 'medium' to care for fish in a minimum 150 gallon tank. <Good luck... trace these specimens for a couple weeks...> I asked him about them and he said that one of the other owners has had a Moorish Idol for 8 months and is doing well in a 220gallon. I don't know, beautiful fish it's a shame that these will be sold and will likely perish. Have you heard of anyone keeping these successfully? <Yes... to sing its praises once again, Spectrum pelleted foods really seem to be a/the "trick" here... Accepted readily and completely nutritious. BobF> David Brynlund

Moorish Idol/Blonde Naso (And Both in A 90g Tank'¦Not Good!), sys.  -- 02/09/08 Hello there, <<Hello, Tom>> I have a few questions about my fish. <<Okay>> About two days ago I bought a Moorish Idol. <<Mmm, one of my all-time favorites'¦I hope you have done your homework on this fish. Please do read through our FAQs on this fish here: http://www.wetwebmedia.com/idolfaqs.htm>> I never really thought about getting one because I heard they don't do well in aquariums, <<Most do not>> but this was an exception. <<Let's hope'¦>> One of the guys at the store I go to pointed him out. He said that the fish was doing great (one of the best Moorish Idols they have seen) and he was eating well (just about anything you put in the tank), so I decided to purchase this beautiful fish (only about 3 inches). <<Getting these fish to 'eat' is not difficult in my experience...the problem comes from providing the proper dietary requirements. I have often heard where these fish fed well, yet still died 'mysteriously.' On an up-note, there seems to be anecdotal proof that Zanclidae that will accept/feed upon New Life Spectrum pellets exhibit better health/longevity'¦providing they have been given proper environmental conditions (e.g. -- not crammed in a too-small tank)>> I put him in my 90 gal tank, <<The Idol needs more volume than this, and preferably at least a 6ft tank>> But I separated him from the other fish in the tank by a piece of plastic (with a lot of water flow) because I was worried my yellow tang would attack it (like it has for every fish I have put in. I figured if he saw the fish in the tank but couldn't attack it he would get used to it being there. <<This is called 'habituation''¦works sometimes'¦sometimes not>> He is now eating very well and looks great. Is the success rate high for this fish now that he is eating well? <<It is not'¦ Getting these fish to eat is not atypical'¦getting them to thrive/survive the long-term, is. If you don't have it now, I very much suggest you obtain the Spectrum pelleted food (small [1mm] pellets)>> Now that I put the divider in the tank, I think it might have affected my blonde Naso (about 4 to 5 inches). <<[sigh]'¦ This tank is too small for the Moorish Idol'¦ It is also too small for the Naso Tang'¦ Placing 'both' in this too-small system has compounded the issue exponentially>> When I first put the divider my Naso ate out of my hand (like he usually does) and ate whatever I put in. Now a day later he doesn't swim as much and he just swims by the food when I put it in the tank. <<The fish is reacting to all the recent commotion and the now more restricting confines of this already too small environment>> Could this be a result of decreasing his swimming room? <<Indeed'¦ And will only continue/worsen as health and behavioral issues, from 'growing up' in this too-small tank'¦divider or not'¦ (Have I said 'too-small tank' enough yet?)>> I turned off the lights and took the divider out, and left the lights off for the night. Will this strange behavior eventually go away now that the tank is back to normal? <<Is hardly 'back to normal' with the addition of this new large (potentially), aggressive, and far ranging/active fish. But yes, the Naso will likely settle back in'¦for a time>> What can I do to assure my fish are always happy? <<Well Tom, if I haven't made it evident by now [grin], you need a 'bigger' tank'¦at least twice the size of what you have now, for keeping both these fishes>> Hope this wasn't too long. <<Not at all>> Thanks for your time. Sincerely, Tom <<Happy to help, Tom. Keeping Zanclus cornutus 'is' a possibility (though let me be clear'¦I don't advocate these fish for the vast majority of hobbyists), but the odds are greatly stacked against you/this fish (and the Naso!) in this 90g tank. For any kind of hope for long-term success, I urge you to upsize these fishes environment. Eric Russell>> <I do hope Eric won't mind my chiming in with a bit re Zanclus in captivity here... Have read in recent months diametrically opposed articles in two popular U.S. aquarium pulp press 'zines re this species... One alleging it was "still impossible", the other a little more optimistic, as Eric and I are here... Do read re our postings re on WWM. RMF>

Survival of Moorish Idol vs. Ribbon eel in Captivity 5/11/08 Hey Crew, <Hello> I have recently gone to my LFS and saw a Black (juv.) ribbon eel in an adjacent tank to a Moorish Idol. As I do to before I purchase any saltwater fish, I asked the sales representative to feed the ribbon eel, and then Moorish Idol. The ribbon eel gradually came up and snatched a feeder goldfish from the tongs. Surprisingly, the Moorish Idol also went after the mysis shrimp being offered. My question is that from the research I have done, in any case, a Moorish Idol will perish in Captivity since at the end, they are still not receiving the sufficient nutrients that they require, such as the specific sponges, and inverts that they eat in the wild, as would a human would being fed popcorn for a while. <Great analogy, fair statement, yes.> However, is this the same for the ribbon eel? <Feeding is one issue, the ability and drive to escape from the tank and just flat out stress being the others.> If the eel has a good appetite, and considering that shipment was reasonable for the animal, would it also perish due to a lack of nutrients? <If it is eating you have a shot, although do be sure it will feed on a marine diet, not feeder goldfish. You will need to seal off the top of the tank and any plumbing that the eel may escape through.> Kishoth <Good luck, a link and related FAQ's regarding the eel below, Scott V.> http://www.wetwebmedia.com/ribbonmorayeels.htm

Moorish Idol Selection (More Than Just 'Eating') -- 08/11/08 Hello crew. <<Hi Shea>> I found a Moorish Idol at my LFS last Thursday and have been monitoring him for days now. <<Ah! '¦this fish is my overall fave. You have perused our FAQs on this fish? http://www.wetwebmedia.com/idolfaqs.htm >> His colors are great, eyes are clear, he looks well fed, and he is eating freeze-dried krill and frozen mysis shrimp. <<Good signs'¦but likely not good enough. Just 'eating' is not enough with this fish as most will still decline. I think there is something about their diet/dietary requirements that we don't yet understand'¦although, there has been anecdotal proof that specimens that will feed on New Life Spectrum pellets may be fulfilling that unknown requirement>> He is also eating dried seaweed and is picking at the ground, eating there as well. <<Or searching for what it 'needs' and is not getting otherwise>> Would this be a good specimen to purchase given the difficult feeding? <<This fish sounds like a good prospect, but as stated earlier just the fact that it is feeding is no guarantee. There have been many instances where these fish ate heartily, only to die 'mysteriously'>> My LFS is also trying to feed him New Life Spectrum Pellets at my request, and he is starting to show interest. <<This will probably be key to successfully keeping this fish'¦along with housing it in a proper environment>> I am going to pick him up on Wednesday if he keeps up with this good eating behavior, and if you think this would be a good purchase. <<Is up to you, but I would prefer to see this fish taking the Spectrum pellets first'¦though if it is feeding as heartily as it seems, you may be able to train it on to this food yourself in short order>> I would be putting him in a 75 gallon tank <<Too small in my opinion. This fish needs space to roam (much like a large Tang species would), along with a good supply of live rock upon which to browse (at least initially) as in that afforded by a larger tank>> to start out but in less than a year will be in a 125 gallon with a powder blue tang and a possible dog face puffers. Would these conditions be suitable for a Moorish Idol? <<The larger/longer tank will be of great benefit, but I'm not so sure about the chosen tankmates. Idols are very aggressive fish, and this one, should it survive/thrive, will be 'king fish' of this domain. The Powder Blue may work out fine and is a better choice than a Zebrasoma species due to the similarity in body profile, but I would give the puffer a miss in the interest of water quality (messy feeders/large bio-mass) and keeping the Zanclus's finnage in prime condition (that streamer would be very tempting to a puffer, in my opinion)>> Look forward to hearing from you, Shea <<If you decide to go forward with this fish I think it is very important you tailor the system to the Moorish Idol for long-term success. That means basing 'all' decisions on the needs of this fish. Doing anything less will only end in disappointment/tragedy. I would be very interested to hear how things progress. Regards, Eric Russell>>
Re: Moorish Idol Selection (More Than Just 'Eating') -- 08/14/08
Hello Eric, <<Hi Shea>> I have decided to purchase the Moorish Idol tomorrow evening, he has been eating the New Life Spectrum pellets for a few days now and I have witnessed this. <<Very good>> But I was just curious on how disease resistant they are? <<Mmm, a good question. From what I have observed and heard/read, they seem to fall along the lines of many tang species re disease and treatment. But malnutrition, should it be present, will significantly increase the fish's susceptibility to complaints of all types>> I can't find many articles on this subject, <<There are a few noted individuals who have done some work/observations with this fish (I believe Helen Thayer is one); though I think most of what I've read was geared toward aggression among conspecifics. A search of the NET on the scientific name (Zanclus cornutus) does yield hits, but much of the info is indeed very basic/brief>> seems like the only hard thing to do, is to get them to eat. <<History/experience with this fish would seem to indicate otherwise. Many hobbyists have been able to get this fish to eat'¦but few have been able to keep it healthy for more than a year'¦and most for a much shorter period of time. As mentioned before, aside from a proper diet you will need to provide a large and open environment for this fish and choose its tankmates carefully>> Thanks in advance and I'll keep you posted. Shea <<Please do'¦and perhaps consider keeping a journal of your methods and observations re this fish for sharing later. I wish you and your Idol much luck. EricR>>

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