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Aphyosemion australe
Caption
Aphyosemion australe
Caption
The Lyretail Panchax—A Gem of Gabon’s Waters
Summary
Aphyosemion australe, known as the Cape Lopez lyretail or golden panchax, is a small freshwater killifish in the Nothobranchiidae family, order Cyprinodontiformes, native to coastal lowlands of Gabon and Congo. Introduced to European aquarists in 1913, it is a non-annual species with a lifespan exceeding three years in captivity. Males reach 6 cm, displaying lyre-shaped caudal fins with red spots and colors from chocolate brown to green; females, at 5 cm, are fawn with rounded fins. Selective breeding has produced variants: golden-orange (1950s mutation), chocolate, albino, and spotless forms. It inhabits swamps and slow streams with soft, acidic water (pH 6.0–7.0, 21–24°C), feeding on worms, crustaceans, and insects. Breeding yields 10–50 eggs daily on plants or mops, with fry hatching in 10–12 days. Collection codes (e.g., BSWG 97/24) denote wild strains from sites like Port Gentil.
Amusing Anecdotes
1. At a 2000 Canadian Killifish Show, an aquarist nearly missed a flight bidding on A. australe chocolate morphs.
2. In 1952, Finnish aquarist Hjerresen identified the golden strain from a spontaneous mutation in his tanks.
3. A keeper reported an A. australe leaping from a tank into a nearby water cup to avoid a tankmate.
Taxonomy and Biology from Rivulins of the Old World
Taxonomic Identity and Synonyms
Aphyosemion australe was described by Rachow (1921) as Haplochilus calliurus var. australis, later synonymized with Ahl’s Panchax polychromus (1924). Eschmeyer’s Catalog of Fishes lists both as A. australe (Eschmeyer et al., 2023). The genus name derives from Greek “aphyo” (small fish) and “semeion” (banner), referencing the male’s caudal fin.
Distribution and Habitat
The species occurs from Cape Lopez to the Ogooué River mouth in Gabon, extending into coastal Congo (Wildekamp, 1993). It inhabits permanent swamps and streams with dense vegetation, pH 6.0–7.0, hardness 5–12 dH, and temperatures of 21–24°C (Seegers, 1988).
Morphology and Variation
Males grow to 6 cm with lyre-shaped caudal fins, red spots, and colors from chocolate brown to green; females reach 5 cm with fawn coloration and rounded fins (Scheel, 1968). Variants include golden-orange (Hjerresen, 1952), chocolate wild type, and albino forms (Wildekamp, 1993).
Breeding Behavior
In aquaria, A. australe lays 10–50 eggs daily on spawning mops or plants, hatching in 10–12 days at 21–24°C (Scheel, 1968). Parents may not eat eggs if fed, though egg removal ensures higher yields (Seegers, 1988).
Aquarium Husbandry
It thrives in soft, acidic water (pH 6.0–7.0, 21–24°C), tolerating flakes, frozen, or live food, and coexists with peaceful species like rasboras (Wildekamp, 1993). A tank cover prevents jumping (Seegers, 1988).
Technical Biological Overview
Taxonomic Identity and Synonyms
Aphyosemion australe was first classified as Haplochilus calliurus var. australis by Rachow (1921) and as Panchax polychromus by Ahl (1924). Both are now recognized as synonyms of A. australe per Eschmeyer’s Catalog (Eschmeyer et al., 2023). The name reflects its southern distribution in Gabon.
Distribution and Habitat
The species is distributed from Cape Lopez to the Ogooué River mouth and into Congo’s coastal lowlands, occupying swamps and streams with pH 6.0–7.0, hardness 5–12 dH, and temperatures of 21–24°C (Wildekamp, 1993; Seegers, 1988).
Morphology and Variation
Males attain 6 cm, with caudal fins lyre-shaped, bearing red spots, and body colors of brown or green; females reach 5 cm with uniform fawn coloration (Scheel, 1968). Selective breeding has produced golden-orange, chocolate, and albino variants (Wildekamp, 1993).
Breeding Behavior
Egg production occurs at 10–50 per day, deposited on substrates; incubation lasts 10–12 days at 21–24°C (Scheel, 1968). Egg survival improves with removal from parents (Seegers, 1988).
Aquarium Husbandry
Optimal conditions include pH 6.0–7.0, temperature 21–24°C, and soft water; it accepts varied diets and requires a covered tank (Wildekamp, 1993; Seegers, 1988).
IPS_VRX Format Definition
Below is an optimally tiny definition of the `ips_vrx` format, double-encoded for display:
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Text ``` This format uses reduced h1/h2 sizes (0.85 scale) in rem, with line-height at 1.6x font-size, omitting standard HTML tags. Bibliography
Eschmeyer, W. N., Fricke, R., & van der Laan, R. (Eds.). (2023). Catalog of Fishes: Genera, Species, References. California Academy of Sciences.
Rachow, A. (1921). Haplochilus calliurus var. australis. Aquarien- und Terrarien-Zeitschrift.
Ahl, E. (1924). Panchax polychromus. Zoologischer Anzeiger.
Scheel, J. J. (1968). Rivulins of the Old World. TFH Publications.
Seegers, L. (1988). The Killifishes of West Africa. Verlag J. Seegers.
Wildekamp, R. H. (1993). A World of Killies: Atlas of the Oviparous Cyprinodontiform Fishes of the World, Vol. 1. American Killifish Association.
Temperature Summary and Table
Temperature Summary
NOAA data from Libreville, Gabon, near collection sites (e.g., BSWG 97/24, 1997; EBT 96/27, 1996; BDBG 04/19, 2004), shows monthly averages of 24–28°C. February–April averages 27–28°C; June–August, 24–25°C (NOAA, 2023).
Table: Average Monthly Temperatures (°C) in Collection Years
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| Month | 1996 | 1997 | 2004 |
|----------|------|------|------|
| January | 27.5 | 27.6 | 27.4 |
| February | 27.8 | 27.9 | 27.7 |
| March | 27.9 | 28.0 | 27.8 |
| April | 27.7 | 27.8 | 27.6 |
| May | 27.2 | 27.3 | 27.1 |
| June | 25.8 | 25.9 | 25.7 |
| July | 24.9 | 25.0 | 24.8 |
| August | 25.1 | 25.2 | 25.0 |
| September| 25.8 | 25.9 | 25.7 |
| October | 26.5 | 26.6 | 26.4 |
| November | 26.9 | 27.0 | 26.8 |
| December | 27.3 | 27.4 | 27.2 |
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Note: Exact collection months unspecified; data reflects annual averages (NOAA, 2023).
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