Lyretail Killifish

The Lyretail Killifish, Aphyosemion australe, is a small, non-annual killifish in the family Nothobranchiidae, native to coastal forest streams and swampy pools of Gabon and the Republic of the Congo in Central-West Africa. It is one of the longest-established killifish species in the aquarium hobby and is notable for being relatively easy to keep and breed compared to many annual African killifish, in part because it does not require an egg diapause period. Several natural color forms exist, ranging from golden-orange to deep red, giving rise to trade names such as the Golden or Cape Lopez Lyretail. The species remains widespread within its native coastal Central African range.

Field marks for Aphyosemion australe:

• Slender, elongated body typically 5-6 cm long
• Coloration ranges from golden-orange to reddish-brown depending on population, with fine red speckling scattered along the flanks
• Distinctive lyre-shaped caudal fin in males, with elongated, pointed upper and lower rays often edged in white or pale yellow
• Dorsal and anal fins are also elongated and pointed in males, more rounded and plain in females
• Distinguished from Gardner's Killifish and Blue Gularis by its more slender build, warmer golden-red tones, and less extreme fin filament length

Lyretail Killifish are native to shaded forest streams, swamp margins, and slow coastal pools in Gabon and neighboring parts of the Republic of the Congo in Central-West Africa. As a non-annual species, it favors more permanent water bodies rather than seasonally drying pools, typically in soft, slightly acidic water beneath dense forest canopy. Native water temperatures are warm, generally 22-25°C, and the species is usually found among leaf litter, root tangles, or fine vegetation near the stream margin, where it finds both cover and abundant small prey.

This species is a solitary to loosely territorial surface and mid-water predator, feeding on small aquatic invertebrates and insect larvae. Males display their elongated fins and coloration during courtship and can show mild aggression toward rival males, though the species is generally considered peaceable compared to larger, more aggressive killifish. Spawning is continuous rather than seasonal, with pairs depositing adhesive eggs among fine plant roots or leaf litter over an extended period; because it is non-annual, eggs typically hatch within a few weeks rather than requiring prolonged dry diapause. Within its native forest streams, it serves as a small predator of aquatic invertebrates and prey for larger fish.