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Genus Monacanthus: Four species. Great beauties as juveniles, adults. soooo
Genus Oxymonacanthus: Two species. Rarely live for any length of time in captivity. Obligate corallivores.
Genus Paraluteres: Two species. Neat, small species that are hardier than most of the family.
Genus Pervagor: Eight species. The best genus of Files for captive use.
Genus Pseudomonacanthus: Four species.
Genus Scobinichthys: Monotypic. Thrown in here for diversity's sake.
Filefishes occur in shallow reef and rocky areas in Atlantic, Indian and Pacific marine environments. Though often present, sometimes in large numbers, they are frequently missed by noisy, unobservant divers.Most files reach around 15cm. (six inches to us old timers); one gets to a maximum length of one meter; Aluterus scriptus. Now that's a big file!
Selection: General to Specific Healthy specimens are characterized by good color, without blotchy or necrotic patches, behavioural elements (curiosity, activity), and active feeding.
Most species make excellent captives, except unfortunately the often-offered long nosed or orange-spotted filefish (Oxymonacanthus longirostris). This one only eats coral polyps. Leave it in the ocean if you can't provide adequate care. In fact, I think the whole genus is corallivorous and should be avoided.
A few notes on filefish capture for the aqua-venturer. Commercially, small individuals are taken with hand nets at night or net-dragged out/over eel grass and such. Larger specimens are taken in mesh fish traps and barbless hook and line baited with some sort of tasty meat.
Filefishes rely a great deal on subterfuge to avoid predation. Relatedly, they seem to prosper in physical surroundings that complement their gaudy integuments. Real or artificial decor schema that allow a blending/camouflaging of files makes them feel at home. Provide them homes where they can appear inconspicuous.
Not picky. Natural water or no. Relatively insensitive to changes, high or low specific gravities, metabolite build-ups...
Give them plenty of opportunities for hiding and wedging into caves and crevices like triggers.
This whole Order is best characterized as very individualistic. In general, filefishes are docile toward members of the same species and their family members when small or necessarily temporarily crowded (at the Dealer's); but watch out! They can become overtly intolerant without any apparent provocation. Most are best kept one file to the tank.
Placing of most filefish species and specimens is unceremonious. Quinn suggests his favorite "drip" method of blending "old" shipping water with "new" system water. I'll still plug my raw freshwater dip method to prevent/dilute pest, parasite and pollution introduction. (See next few Sections)
Monacanthids are not touchy in terms of handling stress. They typically "brighten up" shortly after introduction, displaying curiosity about their new digs.
A caution concerning netting files; their skin and fins get stuck but good in most consumer nets. It's much better for all parties to do away with nets and "hand-lift" specimens or scoot them into a container underwater if/when they have to be moved.
Predator/Prey RelationsThe group are opportunistic omnivores, bordering on tiger barb nippiness in saltwater equivalency. Keep your eye on them, though they usually cause little outright damage, being followed and chewed on continuously can get on one's nerves. Shown, the biting end of a Barred Filefish, Cantherhines dumerilii.
As for "turnabout is fair play", most wanna be predators find filefishes too tough to chomp. In addition to the height-increasing dorsal "trigger" mechanism, they share the triggerfish's capacity for slightly enlarging their bodies by expanding a ventral flap supported by a large movable pelvic bone.
Reproduction, Sexual Differentiation:
Some species have been observed spawning in the wild. Eggs are noted as green in color, about a millimeter in diameter, demersal (on the bottom), adhesive, hatching in a couple of days after sunset, becoming pelagic, planktonic larvae.
In some species, males are slightly larger and more colorful.
Effected most of the time via undulations of the median fins. At times of need/desire, the tail comes into play for short past bursts of straight speed.
Feeding/Foods/Nutrition: Types, Frequency, Amount, Wastes
Most any and all frozen and fresh foods will sustain files. Meaty clams and crustacean foodstuffs will always shake one out of the doldrums. Don't neglect their need for vegetable material though.
Stomach contents analyses reveal a broad mix of hydrozoans, algae, Sedentariate Polychaetes, sponges, gastropods, amphipods, gorgonians, sea grass (a true vascular plant), colonial anemones and tunicates. Not good reef-tank candidates.
Disease: Infectious, Parasitic, Nutritional, Genetic, Social
Martin mentions the efficacy of using tetracycline HCL for treatment of "anomalous" bacterial anomalies, in his case presumed digestive infection manifest in non-feeding. He lists administering the antibiotic directly to the system water at 50 mg per gallon. Any medication advice from anywhere is to be followed in a separate treatment tank, not your main system.
Filefishes are available seasonally and geographically. Don't let their shy, delicate appearance fool you, a few make interesting, affordable aquarium specimens.
Barlow, G.W. 1987. Spawning, eggs and larvae of the Longnose filefish Oxymonacanthus longirostris, a monogamous corallivore. Environ. Biol. Fish.; vol. 20, no. 3 183-194. 1987.
Eristiwady, T. & P. Geistdoerfer. 1991. Biological aspects of Monacanthus tomentosus (Monacanthidae) in the seagrass beds of Kotania Bay, West Seram, Moluccas, Indonesia. Mar. Biol.; vol. 109, no. 1, 135-139. 1991.
Hauser, Hillary. 1984. Skin Diver Magazine's Book of Fishes. The Photographic Book Company. 1984.
Martin, Robert A. 1976. Scrawled filefish. Marine Aquarist, 7:6, 1976.
Nelson, Joseph S. 1976. Fishes of the World. John Wiley & Sons, Inc.
Quinn, John R. 1990. Fooling around with filefish. T.F.H. 10/90.