Yellow-Green Killie, Gabon (Aphyosemion gabunense) — 3-4cm

Overview

The Yellow-Green Killie (Aphyosemion gabunense) is a beautifully coloured African killifish native to the slow-moving forest streams and swampy waters of Gabon and adjacent parts of Central Africa. This peaceful, 4cm species rewards dedicated keepers with elegant finnage, subtle yellow-green tones, and fascinating breeding behaviour. Ideal for quiet planted nano aquariums, Aphyosemion gabunense thrives in soft, slightly acidic water with gentle filtration and live foods. Available for sale UK through Tropical Fish Co, this rare killifish is perfect for experienced aquarists seeking a jewel-like centrepiece for a species-only or carefully chosen community setup.

Appearance and Coloration

The Yellow-Green Killie displays subtle but striking colouration with warm yellow-green tones across the body, often highlighted by iridescent blue or red accents on the fins. Males are more vividly coloured than females, especially during courtship, with elongated dorsal and anal fins that create an elegant silhouette. The body is slender and streamlined, perfectly adapted for life in slow-moving waters. Under subdued lighting in a planted tank, the scales shimmer with a metallic lustre that makes this species a true aquarium gem.

Natural Habitat

Aphyosemion gabunense inhabits shallow forest streams, swamps, and seasonal pools throughout Gabon and neighbouring regions of Central Africa. These waters are typically stained dark by tannins from decaying leaf litter, with low mineral content, soft acidity, and dense vegetation. Flow is minimal, and the substrate consists of mud, sand, and organic debris. During the wet season, these fish spawn in fine plants or submerged vegetation; during dry periods, some populations may experience desiccation of their habitat, though this species is not a strict annual killifish.

Aquarium Setup

A minimum 60-litre aquarium is recommended for a small group or pair of Yellow-Green Killies. Use a fine sand or smooth gravel substrate with plenty of live plants such as Cryptocoryne, Microsorum, Java moss, and floating species like Salvinia or Ceratopteris. Add dried Indian almond leaves or alder cones to replicate the tannin-stained waters of their natural habitat and provide spawning mops or fine-leaved plants for egg deposition. Lighting should be subdued, and filtration gentle to avoid strong currents. A tight-fitting lid is essential, as killifish are excellent jumpers.

Feeding and Diet

As a carnivore, Aphyosemion gabunense requires a protein-rich diet to maintain health and colour. Offer small live or frozen foods such as daphnia, baby brine shrimp, mosquito larvae, grindal worms, and microworms daily. Quality micro-pellets or flakes designed for carnivorous fish may be accepted, but live and frozen foods are essential for conditioning and breeding. Feed small portions twice daily, removing uneaten food promptly to maintain water quality. Variety is key to optimal health and vibrant colouration.

Behaviour and Temperament

The Yellow-Green Killie is a peaceful, shy species that spends much of its time exploring the mid and upper water column among plants. Males may display to each other with flared fins and subtle posturing, but aggression is rare. These fish are most active during dawn and dusk, and they appreciate dimly lit aquariums with plenty of cover. They are not competitive feeders, so avoid housing them with boisterous or fast-moving species that may outcompete them for food. In a well-planted species tank, they display natural behaviours and may spawn regularly.

Suitable Tank Mates

Aphyosemion gabunense is best kept in a species-only aquarium or with very small, peaceful, non-competitive fish that share similar water requirements. Suitable companions include small Microdevario, Boraras species, or tiny peaceful bottom dwellers like pygmy Corydoras in larger, well-planted tanks. Avoid fin-nippers, large fish, aggressive cichlids, and fast competitive feeders. Shrimp are at risk of predation, especially juveniles. A calm, quiet environment is essential for this delicate killifish to thrive.

Breeding

This annual-style killifish typically spawns in fine-leaved plants or spawning mops. Condition a pair or small group with high-quality live foods, then provide spawning media such as Java moss or yarn mops. Eggs are usually collected and incubated in moist peat or damp substrate for several weeks, depending on the strain. Some keepers leave eggs in water for non-annual methods. Fry are tiny and require infusoria or liquid fry food initially, graduating to newly hatched brine shrimp after a few days. Remove adults to prevent egg predation.

Why Buy from Tropical Fish Co

Tropical Fish Co is a trusted UK supplier of rare and specialist tropical fish, including hard-to-find killifish species like Aphyosemion gabunense. We guarantee healthy, well-conditioned stock, expert care advice, and secure nationwide delivery. Every fish is quarantined and inspected before dispatch, ensuring you receive only the finest specimens. Whether you're setting up a dedicated killifish tank or adding a rare species to your collection, Tropical Fish Co offers unmatched quality and customer service. Order online today and bring the beauty of Central African waters into your home aquarium.