Oxymonacanthus longirostris OXYMON-070794-MORNIN-001

This entry was posted on Thursday, July 7th, 1994 and is filed under Filefishes, Spawning Reports.

The Breeder’s Registry® Information contained in this report is taken from submitted observations from aquarist unless noted otherwise (see comments). Information may be reproduced providing the Breeder’s Registry is cited.

Breeder ID: OXYMON-070794-MORNIN-001

Date received: 7/7/1994

Identification: Oxymonacanthus longirostris (Bloch & Schneider 1801)

Geographic Origin: Indo-Pacific

Taxonomy: (after I.C.Z.N.)

   Kingdom Animalia

      Phylum Chordata Subphylum Vertebrata

         Class Osteichtyes Subclass Actinopterygii Infraclass Teleostei

            Superorder Acanthopterygii

                Order Tetraodontiformes

                    Suborder Balistoidei

                        Family Balistidae

                           Genus Oxymonacanthus

                           Species longirostris (Bloch & Schneider 1801)

Description: This species is generally considered extremely difficult to keep in captivity due to the dietary requirements (obligate polyp feeder). This report highlights that there are exception, however, the reader should be reminded that the described diet is rare and most specimens die from starvation in captivity. This species is popular because of the coloration. Most members of this family (Balistidae, which include the “triggerfish”), are thought to be demersal spawners. Most literature indicates that the males are the nest builders (contrary to the information provided within this report). Specimens are generally less than 100 mm Standard Length (Burgess, e. al. 1990, lists 7 cm and 10 cm as lengths for this species). The species generally inhabit shallow waters; 0 – 23 meters, with most recorded specimens collected at depths from 0 – 15 meters. This would coincide with their reported dietary requirements of scleractinian corals.

Duration male(yr): 3.0

Size male (mm): 89

Duration female(yr): 5.0

Size female(mm): 89

Physical differences: Male has orange ventral fin

Adult diet: Frozen brine shrimp, grazed on algae. Occasionally frozen lobster eggs, bloodworms and mussels. Fed twice daily. Maintained with “bubble coral”. Never observed any polyp feeding.

Pre-spawning activity: Female digs in gravel with nose, sometimes spreads fins (display?)

Time spawning began: midday

Area spawning occurred: on gravel bed

Frequency of spawning: daily

Egg description: Fluorescent green “blob” ~ 10 mm across

Approximate quantity: ~100

Size: ~ 1 mm

Egg changes / development: not observed, no attempt to collect eggs, eggs were gone next morning

Spawning tank size (liter): 37

Sides of tank covered? No

Lighting & photo-period: 2 – 18 watt Triton® fluorescent, 1 – 20 watt actinic fluorescent. 10 hours

Filtration: Undergravel filter, cannister. Instant Ocean ® ASW, changed 10 – 50% monthly.

Additives and dosages: none indicated

Water temperature (F): 72-78

Specific gravity: 1.021

pH: 8.0

Nitrate: 0.1 ppm

Comments: Filefish seem more sensitive to high nitrates and spend time at or near the surface. It seems that a “U” shaped tube or similar are to hide is required for hiding and resting. Pair acquired in 1989. First male died and second male introduced. Other occupants; seahorses, hawkfish, goby and bubble coral.

Vernacular name: Orange-spot filefish, Beaked Leatherjacket

Original Description: First described by Bloch & Schneider in 1801 as Balistes longirostris hispidus variety in Systema Ichthyol.; ref. 471., from specimens collected in the East Indies. Valid as Oxymonacanthus longirostris by Hutchins, 1984.

Word origin: The genus Oxymonacanthus is from the Greek root(s) oxy meaning sharp; mon meaning single or one; and acanth meaning a spine or thorn; tus a “sharp single spine.” The species longirostris is a fairly common descriptor from the Latin root(s) long, -i, meaning long; and rostrum meaning a beak or snout. When one looks at Oxymonacanthus longirostris the definition definitely “fits”!

Suggested reading:

Burgess, W. E., Axelrod, H. R. & Hunziker, III, R. E., Dr Burgess’s Atlas of Marine Aquarium Fishes (Guide to Owning A…), 1990, T. F. H. Publications, One T. T. H. Plaza, Neptune City, NJ 07753, TFH-H-1100,
ISBN 0-86622-896-9


About this report: Information contained in this report is taken from submitted observations. Taxonomy, Synonomy, Original description, Word origin and Suggested Reading are provided by Breeder’s Registry staff. Information is presented under the belief that it is accurate. If you have information in addition to, or contrary to that presented you are encouraged to contact the Breeder’s Registry. Permission is granted for “one-time” personal use. Reproduction as distributed or accessible media is prohibited without prior written permission. All rights reserved. 1994

Breeder's Registry staff are all volunteers and appreciate any comments or corrections on any of our posts.

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