Forktail Blue-eye
Also known as: Pseudomugil gertrudae
The Forktail Blue-eye is a small, slender freshwater fish native to northern Australia and New Guinea, named for its distinctive forked caudal fin and striking blue iris. The Forktail Blue-eye originates from Northern Australia and southern New Guinea, inhabiting slow-moving streams, swamps, and vegetated margins of rivers in Queensland, Northern Territory, and Papua New Guinea., reaches Adult size: 3.5 cm in captivity, typically lives 2-3 years, and is kept at 22-28°C (72-82°F). Individual fish vary, so treat this as a general guide rather than a guarantee.
Species at a glance
- Origin
- Northern Australia and southern New Guinea, inhabiting slow-moving streams, swamps, and vegetated margins of rivers in Queensland, Northern Territory, and Papua New Guinea.
- Adult size
- Adult size: 3.5 cm (1.4 inches)
- Life span
- 2-3 years
- Temperament
- Peaceful and schooling; best kept in groups of 6+; non-aggressive toward tankmates but may be outcompeted for food by larger or more active species.
- Tank size
- Minimum 40 liters (10.5 gallons) for a small group; 60+ liters (16+ gallons) recommended for optimal schooling behavior and stability.
- Water temp
- 22-28°C (72-82°F)
- pH range
- pH 5.5-7.5
- Diet
- Omnivorous; feeds on small invertebrates, zooplankton, and biofilm in the wild; in captivity, accept high-quality micro pellets, crushed flakes, frozen daphnia, brine shrimp nauplii, and live microworms.
- Other names
- Pseudomugil gertrudae
About the Forktail Blue-eye
The Forktail Blue-eye is a small, slender freshwater fish native to northern Australia and New Guinea, named for its distinctive forked caudal fin and striking blue iris. Males display vibrant yellow to orange body coloration with elongated fins, while females are more subdued. It thrives in densely planted, soft-water environments with gentle flow and leaf litter. This species is highly social and exhibits natural schooling behavior when kept in adequate numbers.
Lifespan and health
Under optimal conditions, Forktail Blue-eyes typically live 2-3 years, with exceptional individuals reaching up to 3.5 years in well-maintained, low-stress environments; lifespan is significantly shortened by poor water quality, overcrowding, or inadequate nutrition, with mortality often increasing after 18 months if tank conditions degrade. Common health issues include fungal infections (especially on fins) from poor water quality or injury, bacterial infections like columnaris if stressed by aggressive tankmates or sudden parameter shifts, and parasitic infestations such as Ichthyophthirius (Ich) when new fish are introduced without quarantine; preventative measures include maintaining pristine water, avoiding overfeeding, quarantining new arrivals for 2-4 weeks, and observing fish daily for signs of lethargy, clamped fins, or white spots.
Overview
The Forktail Blue-eye is a small, slender freshwater fish native to northern Australia and New Guinea, named for its distinctive forked caudal fin and striking blue iris. Males display vibrant yellow to orange body coloration with elongated fins, while females are more subdued. It thrives in densely planted, soft-water environments with gentle flow and leaf litter. This species is highly social and exhibits natural schooling behavior when kept in adequate numbers.
Care and tank setup
Tank setup should prioritize dense planting with fine-leaved species like Java moss, Hornwort, or Water Sprite, along with driftwood and leaf litter (e.g., Indian almond leaves) to mimic natural blackwater conditions; use a sandy or fine gravel substrate and provide gentle filtration (e.g., sponge filter) to avoid strong currents that stress these delicate fish. Maintain water parameters with weekly 25% water changes using aged, dechlorinated water; keep hardness soft to moderate (GH 3-8 dGH, KH 1-4 dKH) and avoid sudden pH shifts; temperature stability is critical—use a reliable heater to prevent fluctuations beyond ±1°C. Feed small amounts 2-3 times daily, offering only what can be consumed within 2-3 minutes; prioritize live or frozen foods 3-4 times weekly to enhance coloration and breeding readiness, supplementing with high-quality dry food as a staple.
Related breeds
Breed information on this page is based on the Wikipedia article on the Forktail Blue-eye, supplemented with additional research. Reviewed for accuracy.