Red-Striped Killie (Aphyosemion striatum) — XL

Overview

The Red-Striped Killie (Aphyosemion striatum) is a beautifully patterned African killifish from Central Africa, particularly Gabon and adjacent regions of the Congo Basin. This peaceful, diminutive species reaches just 4 cm in length and is prized by specialist killifish enthusiasts for its intricate red striping and delicate finnage. Males display stunning coloration with red or orange-red stripes running horizontally along the flanks and extending into the fins, creating an elegant and refined appearance. Suited to planted nano aquariums and dedicated species tanks, the Red-Striped Killie thrives in soft, acidic water and rewards patient aquarists with fascinating breeding behavior and subtle beauty. Available for sale UK from specialist suppliers, this species is ideal for those seeking a peaceful, lesser-known gem for their collection.

Appearance and Physical Characteristics

Aphyosemion striatum exhibits pronounced sexual dimorphism, with males being far more ornate than females. Males display a base color of greenish-blue to turquoise, overlaid with distinct horizontal red or orange-red stripes that run from the gill covers to the base of the tail, giving the species its common name. The unpaired fins—dorsal, anal, and caudal—are elongated and beautifully patterned with red, yellow, and blue markings, often with contrasting white, yellow, or red margins. The caudal fin may show slight extensions on the upper and lower rays in prime specimens. Females are much plainer, with a brownish or olive-tan body color, minimal patterning, and rounded fins. Both sexes have a slender, streamlined body shape with an upturned mouth adapted for surface feeding, and large, expressive eyes. Males in breeding condition intensify in color, becoming almost luminescent under subdued lighting.

Natural Habitat and Distribution

Aphyosemion striatum is endemic to Central Africa, particularly Gabon and adjacent regions of the Congo Basin, where it inhabits small forest streams, swamps, and rain pools within densely vegetated, shaded areas. These habitats are characterized by soft, acidic, tannin-stained water with minimal flow and a substrate of leaf litter, peat, and decaying organic matter. Water levels fluctuate seasonally, with some populations experiencing significant drying during the dry season, placing pressure on killifish to breed opportunistically. The dense canopy overhead creates dim, dappled lighting, while submerged roots, fallen branches, and fine-leaved aquatic plants provide cover and spawning substrates. Water chemistry is typically very soft (0-4 dGH) and acidic (pH 5.0-6.0), with warm temperatures year-round (22-26°C). Replicating these conditions is essential for long-term success in captivity.

Aquarium Setup and Environment

A minimum aquarium capacity of 40 liters is suitable for a pair or small group of Red-Striped Killies, though 60-80 liter planted tanks provide greater stability and breeding opportunities. The aquarium should be densely planted with fine-leaved species such as Cabomba, Myriophyllum, Limnophila, or Java moss, supplemented with floating plants such as Salvinia, Pistia, or Ceratopteris to diffuse lighting and provide cover. Spawning mops (wool or synthetic yarn tied to cork or weighted) are essential for breeding and should be placed in quiet, shaded areas. A dark, fine substrate (black sand or fine dark gravel) helps reduce stress and enhances coloration. Include driftwood and dried leaves (Indian almond, oak, or beech) to replicate the natural tannin-rich environment and provide additional cover. Filtration should be very gentle—sponge filters or air-driven box filters are ideal to avoid strong currents. A tight-fitting lid is absolutely essential, as killifish are notorious jumpers.

Water Parameters and Quality

Red-Striped Killies require soft, acidic water to thrive and display their best colors. Maintain temperatures between 22-26°C, with 24°C being ideal; avoid prolonged exposure to temperatures above 27°C. The pH should range from 5.5-7.0, with a preference for the acidic end (5.5-6.5). Water hardness must be soft, ideally 0-6 dGH; use rainwater, RO water, or deionized water remineralized with minimal buffers if tap water is too hard. Stability is more important than exact parameters—avoid sudden fluctuations in temperature, pH, or hardness. Maintain zero ammonia and nitrite at all times, and keep nitrates below 20 ppm through regular small water changes (15-20% weekly). Peat filtration, alder cones, or blackwater extracts can help replicate natural conditions and support health and coloration. Excellent water quality is essential for this sensitive species.

Feeding and Nutrition

Aphyosemion striatum is a strict carnivore, feeding in nature on small aquatic insects, insect larvae, and microcrustaceans found at or near the water surface. In captivity, live and frozen foods are essential for maintaining health, condition, and color. Offer daily feedings of daphnia, cyclops, baby brine shrimp, mosquito larvae (black and white), grindal worms, microworms, and vinegar eels. Bloodworms can be included 2-3 times per week but should not dominate the diet. High-quality micro pellets or freeze-dried foods may be accepted after acclimation, but live and frozen foods are strongly preferred and essential for breeding condition. Feed small portions 2-3 times daily, as killifish have small stomachs and benefit from frequent small meals. Monitor all individuals during feeding to ensure none are being outcompeted, and remove uneaten food promptly to maintain water quality.

Behaviour and Temperament

The Red-Striped Killie is a peaceful, somewhat shy species that spends most of its time in the upper and mid-water levels of the aquarium, often hovering among plants or beneath floating vegetation. Males can be mildly territorial toward one another, especially in smaller tanks, but aggression is typically limited to fin displays and brief chases rather than physical harm. A pair or small group with multiple females per male (1 male to 2-3 females) is ideal to distribute male attention and reduce stress on individual females. These fish are most active during dawn and dusk periods, becoming bolder in dimly lit aquariums with plenty of cover. They are not schooling fish but appreciate the presence of conspecifics and will interact subtly through displays and movements. Their calm, deliberate swimming style and delicate nature make them unsuitable for busy community tanks.

Tank Mates and Compatibility

Aphyosemion striatum is best kept in a dedicated species tank where their specific needs and delicate temperament can be fully accommodated. If tankmates are desired, they must be very small, peaceful, and non-competitive—options include microrasboras (Boraras species), small peaceful tetras (ember tetras, green neon tetras), or Corydoras pygmaeus in larger, heavily planted setups. However, even these species can outcompete killies for food, so careful monitoring is essential. Avoid all large or boisterous fish, fin-nippers (even small barbs), aggressive cichlids, fast competitive feeders, and very hard-water species such as livebearers or African Rift Lake cichlids. Snails and larger shrimp may coexist, though very small shrimp or fry will be eaten. The safest and most rewarding approach is a species-only setup where the Red-Striped Killie can be the centerpiece.

Breeding

Aphyosemion striatum is an egg-scattering annual or non-annual killifish (depending on population) that can be bred successfully in captivity with proper preparation. Condition breeding pairs or groups with high-quality live foods for 2-3 weeks, then place them in a dedicated breeding tank (20-40 liters) with soft, acidic water (pH 5.5-6.0, temperature 24°C), gentle sponge filtration, and dim lighting. Provide fine-leaved plants (Java moss, Myriophyllum) or spawning mops as egg deposition sites. Pairs will spawn over several days, depositing a few non-adhesive eggs daily among the plants or mop fibers. Eggs should be collected every 2-3 days by removing the mop or gently siphoning eggs into a shallow container. Incubate eggs in shallow water (2-3 cm depth) with a few drops of methylene blue or a mild antifungal agent to prevent fungal infection. Eggs typically hatch in 12-18 days depending on temperature. Fry are very small and require infusoria or liquid fry food for the first 5-7 days, then newly hatched brine shrimp and microworms. Growth is slow, and water quality must remain pristine to avoid fry losses.

Why Buy from Tropical Fish Co

Tropical Fish Co is the UK's premier destination for rare and specialist killifish species, including healthy, acclimatized Red-Striped Killies from reputable breeders. Every fish is quarantined, conditioned on live and frozen foods, and thoroughly health-checked before dispatch to ensure you receive vigorous, disease-free specimens. Our expert team provides detailed care guides, personalized setup advice, and ongoing support to help you create the ideal soft-water, planted environment these delicate fish require. We offer a live arrival guarantee on all orders, backed by secure, insulated packaging and next-day courier delivery to your door. Whether you're new to killifish or an experienced breeder, our commitment to quality, ethical sourcing, and customer service ensures you receive the finest livestock available. Order your Red-Striped Killie today and experience the beauty and charm of one of Central Africa's most elegant aquarium species.