Longnose filefish...
Mr. Fenner,
I recently made a foolish, impulsive purchase of a Longnose filefish (Oxymonacanthus longirostris) from FFExpress. I saw how beautiful the animal was, and at an attractive price of $11, it was a sealed deal. I saw the "restricted" logo next to the name on the web site, but for some reason I assumed this was because it was a delicate shipper. The strange thing is, I am very particular to what I put in my tank. I have researched it all out and have put together what I consider to be a very healthy and enjoyable system. This is ironic because I learned almost everything I know from reading your most recent book, but I failed to peruse the section on filefishes closely enough to see that you strongly dissuade us from purchasing the Longnose filefish.
<Ah, a "slip", not a "fall"... we all make them.>
Is there anything else that this fish might consider eating? I visited wetwebmedia.com and saw that it eats specifically "Acroporid" coral. 
<Yes, almost exclusively>
What if I purchase Acroporid coral polyps on a medium-sized rock and let the fish eat. Will it strip the rock clean before anything has a chance to grow back? 
<Hmm, depends on size of both... predator/prey... but most Oxymonacanthus die "mysteriously within a week or two regardless.>
You may be shaking your head at my irresponsibility on this move, but at this point, I just can't stand the thought of watching my fish wither away. What a waste. I would greatly appreciate any extra information you may be able to divulge. Thank you.
<To continue in your quest for more suitable species, specimens and further your efforts at informing others (as you have done here) in avoiding them... so that appropriate ones will be provided, others left in place.. Bob Fenner>

Re: My Gray bellied Regal Angel... (actually Harlequin Filefish? Oxymonacanthus?)
Hi,
Thanks for the response. In reading a lot of literature out there I was under the impression that O. longirostris simply will refuse food. What I did not know is that it will eat, but will not assimilate the nutrients. I was told by a person in the Waikiki aquarium years ago that they feed their specimen with a special gel type food they make in-house.
Perhaps someday a fish food manufacturer will figure out a mix of stuff that it will eat, digest, and assimilate. Until then... sigh.
<<Thanks for the additional info. Cheers, J -- >>

Longnosed Filefish
Hi,
<Hello>
  I know this fish is hard to keep, and usually dies within a week. But, if this fish is provided with its exact needs would it live a much longer life?
Yours Faithfully Aaron.
<Of a certainty yes. There are a myriad of factors that go into an equation of likelihood of survival/mortality... species specific, size, sometimes sex influenced aspects... for relative resistance to capture, holding, moving... feeding response to whatever (if anything) folks are offering... In this case, this species does hold up pretty well to being caught, held and shipped, but most often is "stuck" in situations/circumstances of too small a space, not enough maturity to the system, too many more-aggressive feeding tankmates... and most especially a lack of appropriate foodstuffs. Improving on all these aspects/factors and more definitely improves ones chances of keeping this fish longer, healthier... even to and through reproduction. Bob Fenner>

Formalin & Orangespot Filefish
<Hi, MikeD here>
I have a few questions about a couple of subject matters.  The first concerns formalin.<OK>  I live in California and can no longer find formalin for sale.<California's standards are stricter than many, and formalin is a known and proved carcinogen, or cancer causing agent>  I have heard two things.  The first is that it is illegal to sell here, and the other is that the pharmaceutical company that makes it is no longer in business.  What is the truth behind it?<Since there always was more than one company that manufactured it, I seriously doubt that THE company went out of business, unless of course "they" are referring to a California company, which is quite possible>  I depend on this medication to get rid of the various external parasites found on marine angels and butterflyfish before introducing them to my aquarium.  It is part of the reason I'm able to keep the Eight Banded Butterflyfish (Chaetodon octofasciatus) alive and eating well for a long time now.<I seriously doubt it's the formalin enabling you to keep the fish alive, but rather your husbandry and feeding regimens instead.>  How do I get a hold of it, or are there other safe alternatives to ridding fish of their parasites?<There are several other chemicals that are effective against external parasites, the choice of which is often dependent on what type of parasite it is to begin with>
The other concerns the Orangespot filefish (Oxymonacanthus longirostris).  I have kept this fish before in a tank filled with thriving Acropora colonies.<That's highly commendable and a much greater length than many are willing to go in the attempt>   One day it mysteriously disappeared.<Which is usually the end met by most in captivity>  All my other fish at the time were healthy and still alive.  I believe I had a couple of Red Margin Fairy Wrasses (Cirrhilabrus rubrimarginatus), a Blue Tang (Paracanthurus hepatus), and a Golden Pygmy Angel (Centropyge aurantius).  I suspect the possibility of parasites killing this fish<No offense, but I think you've got a parasite fixation>, for it pecked at the corals all day long.<Meaning what?>  What's even weirder is that I have been seeing pictures of these fish fat as a pig in nature.  But my fish never got that friggin' big in the aquarium feeding off of Acropora colonies alone.<That's likely because it was never healthy and was lacking in a critical element in its diet it needed to survive.>  This to me seems contrary to what is being written everywhere in books magazines, as well as articles on the internet about them being exclusive corallivores.<OK, I'll agree a little with that statement.>  Is it possible they are just as undemanding in the variety of food they eat as other filefish, but are rather just shy behaviorally and very slow to adapt to rapid changes in diet and environments?<Possible, but that's not likely the entire explanation, with the real answer being that there's something in their wild diet you weren't able to meet, perhaps something as simple as not enough different species of corals. In the wild they're on the move all day long and probably include much in their diet in addition to the coral, which provides the bulk of it.>  I have read accounts from certain aquarists training this fish to regularly accept normal aquarium foods.<Me too and I'm always suspicious of these reports, with many people thinking 6 months or a year is "success" while in actuality it's just slow starvation.>  I've also noticed in pet stores and wholesale warehouses, that these fish peck at the sides of the glass and the bottom of the tank a lot.<Logical. they are starving to death and trying to find ANYTHING to help fill the gap.>  The pecking seems very deliberate.<It probably is, with their vision attuned to things we can't even see.>  What are they doing?<Eating>  Could the possibility of parasites I've seen commonly attached to angels and butterflies affect the health of these fish drastically to the point of no return?<By the hundreds? Not likely. I don't know you but you really do seem obsessed with parasites.>  Would it be proper to assume that if I tried a similar mini-reef Acropora set up in the distant future, to purchase the smallest juvenile filefish possible for the purposes of adaptability, much like butterflyfish?<Not a bad idea, but if I were to try it I'd add more than just Acropora, as nature rarely has anything found singly by species. I wouldn't be surprised to find that small anemones, cnidarians and such are also a vital part of their diet.>  Are these fish also commonly found in groups rather than singly in nature?<Actually, no. Adults have been found to go through a very elaborate pairing ritual, not unlike many of the other filefish.>  They seem to be very peaceful towards specimens of the same species.<Seem is a dangerous word. Indications are that males can be highly territorial and combative, another trait often found in other filefish.>  Could they possibly suffer from severe loneliness as Anthias do if they're kept alone?<Possible, but highly unlikely, as the family as a whole tends to regard each other with antagonism, particularly in the confines of an aquarium.>  Any well informed and current information about them would be greatly appreciated.  Thank you.<You have to keep several things in mind. Even with the best equipment available, humans can only spend a few hours underwater at any given time, thus any and all information, even based on wild animals, is at best extremely sketchy and 95% guesswork and assumption. To make matters worse, it's not possible to follow them into areas where they regularly travel as we are simply too large, with the final kicker being that the human eye, as you pointed out, may not be able to discern something that's blatantly visible to them. While I commend your dogged determination and the steps to which you are willing to go to solve the dilemma we currently face with the species, I'm forced to agree with the commonly accepted statement that, for now, a LOT more natural observation needs to be done before they are suitable as candidates for a home tank. With luck, the answer will be found before we wipe them out as a species, either by over collecting, or, more likely, the destruction of the entire reef ecosystem they need to survive. At present, the human race is the greatest single extinction factor since the asteroid/comet that likely eliminated the dinosaurs.>
Philip

Delicate File Fish, Orange Spotted Filefish Question
<HI, MikeD here>
Hello,
From the first day I began my salt water hobby I always wanted to keep the orange spotted filefish.<Neat fish, very common here> <<Umm, there is an identification difference going on here. MikeD is referring to a species in the tropical West Atlantic, and the querior is speaking of a Pacific... Cantherhines macrocerus and Oxymonacanthus longirostris respectively. See http://www.wetwebmedia.com/filefish.htm. RMF>> But after researching I found that this was a very difficult animal to care for.<Not really, just not often offered for sale>  One year into my hobby my want for it has risen and I have decided to make a commitment to getting at least one.<OK. They are another personality fish>
For the tank that it would  live in this what I plan to have.
Tank.
10 gallon<Problem #1...too small for all but a tiny juvenile. These are active, like little "mini-triggers"
Lighting.
Fluorescent compacts. at least 200 watts)<not a problem>
Rock and Sand.
5- 10 pounds of Vanuatu rock.  10- 15 pounds of live sand.<That part's good>
Water Circulation.
A couple of small pumps<OK>
Heating.
Brand which I have forgotten the name of.<As long as it works>
Filtration.
I plan to get a skimmer so that will be in the next month or so.  Also here is where I will need your help.  What kind of filter would you recommend for such a  small tank.<One that holds less water than the tank!**grin**>
Corals.
A mixture of Acropora corals.  I plan to grow the Acropora in my refugium on my 75 gallon tank along with the coral in the ten gallon.<AND here's problem #2. Many filefish just love SPS almost as much as they do anemones!>
SO how does this sound and am I leaving out anything?  Please tell me if I am because I would like this to be a challenging yet not a killing change of path.<My suggestion is at least a 55 gal. tank w/o corals unless they are planned as live food. Sorry, but those are the facts. Just the facts. Badge #714>

Re: Delicate File Fish
<Hi, MikeD here again>
I only plan to keep on filefish would that be okay in the small space.  
And yes the corals are for live food.<Sorry about the previous mix up, but I'd JUST seen the Atlantic OS Filefish offered for sale for the first time just before reading your earlier questions. In regards to O. longirostris, sadly these are another little beauty that is best left on the reef, and can be difficult even for public aquariums willing to spend thousands to house them.  Even though small I doubt that you could supply enough live SPS to last very long as their hummingbird movements belie a similar metabolism to the little bird counterparts as well. I can truly understand their appeal, but it's usually one that always has the same outcome in a home tank, with another living gem snuffed out in the process.>