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I had a query today from Matt Pedersen referring to the gorgeous, but usually doomed, Orangespotted (or Longnosed) Filefish, Oxymonacanthus longirostris. See below for Matt’s message, followed by an extract from one of my old articles. At the end I’ve added a few up to date comments on the subject.
Good Morning, I’m hoping to reach Mr. Tim Hayes regarding a Reef Ramblings blog entry from March of 2007. http://reefs.webxpress.com/?p=11 In this article, Mr. Hayes references an earlier article (2004) in which he references yet another article about a captive spawning of this filefish species: “Incidentally, I’ve also come across a report of Oxymonacanthus longirostris spawning in captivity, placing adhesive eggs on to the glass of the aquarium” I’m currently working with a few specimens of this species, and am very interested in any information or references Mr. Hayes can provide about this spawning report. Thanks in advance! Matt Pedersen MOFIB – www.MarineBreeder.org
an extract from
Catering For Picky Feeders On The Reef (PFK 2005)
I recently received an “Ask the Experts” query that set me thinking about strategies for feeding animals that are reputed to be difficult feeders. Now the advice I’m giving here isn’t to be taken as gospel, you’ll still need to do some work (i.e. think!) figuring out the best way for you to proceed. What I’m trying do is to show you how to think round the problems involved. Firstly, always research the requirements of any animal you’re interested in purchasing. This doesn’t just mean ask the guy in your local fish shop – the retailer won’t always know and unfortunately I hear many reports of bad advice being given…
Best advice can often come from someone with experience of keeping your chosen beast but even that’s not always going to be correct. You have to take responsibility for the fish or invertebrates you buy, if you don’t feel confidant that you can fulfill its needs don’t buy it! Some of the animals I’m discussing here are definitely not for the beginner but many of the techniques can benefit quite a range of the animals that we keep, even relatively easy ones.
So, on to the letter that started the whole thing off…
I was a very enthusiastic marine aquarist for several years until about 10 years ago when a combination of children and setting up a business meant I had to give up the hobby.
I am now interested in getting back into the (much changed) hobby as circumstances now allow for the time and dedication required.
I would really like to set up a ‘specialist’ tank to keep just one species, the Long Nosed Filefish, Oxymonacanthus longirostris. I am aware that these are very difficult to keep although I did achieve some modest success all those years ago in a mixed but ‘quiet’ tank. I had thought about setting up a largish tank with predominantly Acropora species, which I believe, is the natural diet of this species in the wild and a small group of these fishes.
My question is whether you think this would be possible/advisable; whether it would still be possible to import this species for such a set up and whether with care and attention to other dietary needs it might succeed? I have always been fascinated by this particular fish and would derive a great amount of pleasure from being able to keep them.
My first thought was whoa! Forget it! But after I’d reflected on the idea for a while I changed my mind. I’m generally against stocking hard to keep species in shops, but if an aquarist is after something in particular and demonstrates knowledge of the animal, I’m usually happy to order one in.
I prefer to discourage the average fishkeeper from buying these more specialist creatures. The thing is, we are now keeping animals in our tanks that a few years ago we wouldn’t have thought possible; if responsible aquarists are prepared to work at problem animals then maybe, in years to come, we’ll be able to successfully keeping even more species.
As you’ve mentioned, the problem with this stunningly beautiful fish is its diet of Acropora polyps, this fish is an obligatory corallivore. In his book, Marine Fishes, Scott Michael mentions that it can be occasionally persuaded into eating live brine shrimp, though this will rarely fulfill its nutritional requirements.
I think you’re on the right track, setting up an Acropora tank, but I’d suggest going one step further and incorporate an Acropora refugium into your system. Acropora are very hardy and easy to grow given the right conditions, so by farming them in the refugium (where they’re safe from predation) you could then rotate them between the display tank and the refugium. By rotating them back to the refugium they’d have an opportunity to recover and grow.
If you want to try supplementary feeding make sure any live food is enriched with either a product such as Kent’s Zoecon or phytoplankton. If the fish are reluctant to take food from the water column you might like to try pushing something like shrimp into the surface of a coral skeleton or rock to simulate polyp flesh.
Incidentally, I’ve also come across a report of Oxymonacanthus longirostris spawning in captivity, placing adhesive eggs on to the glass of the aquarium. Plus, when I attended MACNA last year, one of the speakers Joe Yailo of the Atlantis aquarium, New York, had photos of this fish eating a commercial marine food. Joe had thought it worth the risk of adding a pair of these fish to the 20, 000 gallon reef tank he maintains, on the grounds that there would be enough natural food available in a tank of that size, without the risk of the coral population being destroyed. Finding that the fish would eat a prepared food under these conditions was an unexpected bonus.
I’m afraid that although I’ve been writing this answer up in an encouraging manner saying, yes its doable for someone prepared to put in the money, time and effort, its unlikely that you’ll be able to get hold of the fish (at least in the UK). A couple of years ago the main marine wholesalers in the UK, TMC and KKC, agreed not to import this fish on the moral grounds of it being too difficult to care for. Also the key to success with this fish would appear to be to obtain good quality stock, which is very much dependant on the standard of the holding facility that they are imported from.
Copperbanded & Longnose Butterflies.
Chelmon rostratus, the Copperbanded Butterflyfish and Forcipiger flavissimus, the Longnose Butterflyfish, are two species that I believe have an ill deserved reputation as poor feeders in captivity. I think the main problem here is that most aquarists don’t appreciate their specialised mode of feeding. These fish have long snout for a reason; it’s an adaptation to their specific manner of feeding, which is to browse for small marine organisms among the crooks and crannies of the reef. Due to their specialised feeding they are at a great disadvantage when it comes to taking food in open water, until they can learn to eat in this new manner they will be continually out competed by fish more suited to the task. There is also the misconception that to check if these fish are eating before purchase it’s necessary to see them eat live artemia. Either give these fish time to acclimate to aquarium foods on their own, away from competition or start employing specialist feeding strategies of your own. A simple idea you can try, is to pack a food such as frozen Mysis into an empty snail shell then position the shell in an area of the tank frequented by the fish, preferably away from where the other fish are feeding. I would also suggest only keeping these fish in a reef tank or an aquarium utilising live rock where they’ll be able to find plenty of tasty morsels between feeds.
The paragraph about Copperbanded & Longnose Butterflies was intentionally included as there may be a similarity between their mode of feeding and that of filefish species featuring a long snout.
Matt has made some interesting observations in his Oxymonacanthus longirostris – Survival log! published on MOFIB http://www.marinebreeder.org. He refers to the fishes’ browsing behaviour and on observing the apparent feeding attention given to SPS frags which, on close inspection, have no tissue damage speculates:
“..makes me wonder if the filefish is not actually eating the tissue of the SPS corals, but perhaps feeding on coral parasites or the “polysaccharide mucus” that corals give off (afterall, polysaccharides are complex carbohydrates, so potentially plenty of energy stored there, right?)??? I wonder where the “proof is” that these are actually “coral feeders” in the sense we all think of them as being??? A little part of me is doubting the “coralivorous” nature of these fish after seeing it fail to eat the polyps that it was constantly nipping at.”
This led me to reflect on the similarity to the Butterflyfishes mentioned above. It’s certainly worth thinking about the size and shape of the mouth as being an indicator of its feeding habits. Want to try feeding them some Acros infected with Red Bugs, Matt? Mucus feeding seems an interesting possibility and of course it could be a combination of mucus and small benthic organisms inhabiting the corals surface.
It could well be worth talking to Joe Yailo of the Atlantis aquarium to find out what damage, if any, is being done to his corals. I think the commercial pellets were New Life Spectrum, and it’s also worth noting they also feed a lot of frozen CyclopEeze. If you want to try pellets I’d also suggest checking out the Dainichi foods that include CyclopEeze in both standard and veggie form.
There is a caveat when it comes to feeding aquarium foods to difficult to feed fishes. Just because a fish is seen to be eating and excreting it doesn’t necessarily mean that it’s gaining nutrition. If a fish is incapable of assimilating its diet, even though feeding heavily, it will die prematurely from malnutrition.
As regards the reference to their spawning, first off I’ve been a very naughty author and omitted to give the reference source, and secondly I can’t remember what the source was. I see I’ll be spending the rest of the weekend searching back through my files …
Any questions or comments, or if there are any particular topics you’d like to see covered here, please feel free to get in touch with me: firstname.lastname@example.org