Opistognatus aurifons OPIAUR-061893-BELSEA-001

This entry was posted on Friday, June 18th, 1993 and is filed under 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:OPIAUR-061893-BELSEA-001

Date received: 6/18/1993

Identification: Opistognathus aurifrons (Jordan & Thompson, 1905)

Origin: Caribbean

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

Kingdom Animalia

Phylum Chordata Subphylum Vertebrata

Class Osteichtyes Subclass Actinopterygii Infraclass Teleostei

Superorder Acanthopterygii Order Perciformes Suborder Trachinoidei

Family Opistognathidae

Genus Opistognathus (Cuvier 1816)

Species aurifrons (Jordan & Thompson, 1905)

Description: Dorsal rays XI, 15 to 17; anal rays III, 14 to 16 (rarely 14); pectoral rays 19 to 21 (rarely 21); lateral scale rows posterior to opercular flap 81 to 94; gill rakers increasing with age, those of lower limb varying from 17 in young to 37 for adults; pelvic fins long; 68 to 96 mm standard length. Sexually monomorphic, although males are observed to have a pronouncedly enlarged head during courtship. This species is native to the Florida waters and in the wild spawns from spring to late fall (Colin, 1972). Pairing in this species appears to be long term. The species is slender in body form. Coloration of body is pearlescent white to light bluish-gray and yellow coloration around the eyes, nape (forehead), anterior portion of dorsal fin and occasionally jaws. The species requires a coarse substrate in which to construct its burrow. The species is generally very shy and retreats quickly into the safety of its burrow. It has been suggested by one source that a separate burrow is used for spawning (although this has not been documented).

Duration male(yr): 0.9

Size male (mm): 100

Duration female (yr): 0.9

Size female(mm): 85

Broodstock notes: Male has an “Impressive” swollen head when in spawning condition. Coloration is also more vivid than the more pale female

Physical differences: Male is larger, sexual identification is difficult. Initially purchased 12, pairing largest with smallest. Allowed remainder to pair out in communal 300 liter tank.

Adult diet: “Mash” of shrimp, kelp, caulerpa, squid, mussel, gelatin. Live Artemia, Mollie fry, vitamin soaked flake food.

Pre-spawning activity: Male increases burrowing activity. Coloration deepens, head assumes a puffed-out appearance. Displays by male high in water column. Expands fins and gills just before lights go out.

Time spawning began: dusk

Area spawning occurred: mid to high in water column

Frequency of spawning: unknown

Egg description: compact adhesive mass linked by filaments

Approximate quantity: 100

Size: ~ 2 mm

Egg changes / development: Light to transparent. Oral incubation by male

Incubation period: unknown

Time hatching occurred: dark

Size of hatching larvae: 2 – 3 mm

Yolk sac present? yes

Newly hatched appearance: Large with unusually large eyes and mouths. Yolk sac small. Body colorless

Transfer / removal method: not initially removed

Spawning tank size (liter): 70

Sides of tank covered? Yes

Lighting & photo period: 1 cool white, 12 hour, 3 – 4 ” from surface, ~ 24″ from burrow

Filtration: Centrally filtered. Turnover 3 x volume/hour. Algal scrubber, skimmer, UV

Additives and dosages: none

Water temperature (F): 76-82

Specific gravity: 1.020

pH: 8.2

Nitrate: none detected

Fry development / changes: Darken slightly after day 3. No real coloration or adult “form” until day 20 -23 when metamorphosis to adult occurs. Losses can be heavy.

First food offered: “S” strain rotifers. HUFA added. Rotifers fed on Isochrysis and Chlorella

Second food offered: newly hatched Artemia and benthic copepods


1st week(%):35%

2nd week: 29%

3rd week: 27%

4th week: 16%

Development description: After metamorphosis a pearly sheen develops with a faint blue becoming visible on posterior half of body. Pronounced yellow coloration develops.

Rearing tank size (liter): 100

Sides of tank covered? Yes, black

Lighting & photo period: 1- 13 watt compact daylight fluorescent, 24 hrs day 1- 3 then 12 hrs

Filtration: aeration only, then slow drip from central after day 7

Additives and dosages: UltraLife® Iodine supplement; 1 drop / day

Water temperature (F): 76 – 82

Specific gravity: 1.020

pH: 8.2

Nitrate: none detected

Comments: Fry are generally robust, active and aggressive feeders with large mouths. Prone to bacterial infection like clownfish. Adults must be provided with 6″ of substrate, preferably large diameter ( ~ 1″). Tall water column, minimum 18″ for courtship.

Original description: First described by Jordan and Thompson in 1905 as Gnathypops aurifrons, in Bull. Bur. Fish. v. 24 (for 1904) Fig. 4 (not fig. 6) [; ref. 2538]. From a single specimen collected at Garden Key, Dry Tortugas, Florida, U.S.A. Holotype (unique). Valid as Opistognathus aurifrons.

Vernacular name: Yellow head (ed) jawfish

Word origin: The genus Opistognathus Is from the Greek root(s) opisto meaning a snake or serpent (isto is a superlative ending); and gnathus meaning jaw. The genus aurifrons is from the Latin root(s) auri meaning gold; and frons meaning forehead or brow.

Suggested reading:

Burgess, W. E., Axelrod, H. R. & Hunziker, III, R. E., Atlas of Marine Aquarium Fishes, Second
Edition, 1990, T. F. H. Publications, One T. T. H. Plaza, Neptune City, NJ 07753, TFH-H-1100,
ISBN 0-86622-896-9

Colin, P. L., Daily activity patterns and effects of environmental conditions on the behavior of
the yellowhead jawfish, Opistognathus aurifrons, with notes on ecology. 1972, Zoologica, NY.

Randall, John E., Caribbean Reef Fishes, 1968 (1st edition), T. F. H. Publications, Inc., T.F.H.
Building, 245 Cornelison Avenue, Jersey City, NJ, 07302, TFH-H-932,

Thresher, R. E., Reproduction in Reef Fishes, 1984, T. F. H. Publications, Inc., 211 West
Sylvania Avenue, Neptune City, NJ, 07753, USA, ISBN 0-87666-808-2

Walch, John, Breeding Jawfish, 1993, The Breeder’s Registry, Volume 1, Issue 4,

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 member(s) of The 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. 1993

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