Spotted Blue-Eye

Geographic Origin and Biotope: Inhabits peat swamps and shaded streams of northern Australian and Papua New Guinean rainforests. Warm, extremely soft, acidic, tannin-stained blackwater with leaf litter bottoms.

Taxonomy and Morphology: A Pseudomugilidae (not a true Rainbowfish), maxing at 3-3.5 cm. Two separate dorsal fins. Proportionally huge eyes with an electric blue iridescent ring. Upturned mouth for surface micro-prey.

Social Behavior: Peaceful schooler but surprisingly lively. Males perform elaborate courtship displays, erecting fins like fans and trembling before females. Requires at least 2 females per male to prevent female exhaustion.

Coloration and Sexual Dimorphism: Males with enormously developed yellow-orange dorsal and anal fins with black tips and phosphorescent white margins. Females smaller with reduced fins and subtle beige coloration.

Tank Setup: Dedicated 40-60 liter aquarium, densely planted with mosses, floating plants, and catappa leaves. Dim filtered lighting. Near-zero current.

Feeding and Diet: Surface micro-predator. Imperatively needs freshly hatched artemia nauplii, microworms, and live daphnia. Standard flakes are too large for their tiny mouth.

Water Quality: The critical parameter. Requires RO water (GH 2-8), acidic (pH 5.5-6.5), immaculate. Any trace of ammonia is lethal in hours. Small but very frequent water changes (10-15%).

Compatibility: Exclusively with peaceful micro-fish: Boraras, small Rasboras, Caridina/Neocaridina shrimp. Any fish over 5 cm will stress it to death.

Reproduction: Occurs daily in perfect conditions. Filamentous adhesive eggs among mosses. Fry are microscopic and need infusoria for the first week.

Risks and Diseases: Extreme fragility. Transport stress kills them en masse. Columnaris (white lip fuzz) is their nemesis, killing in 48 hours. No tolerance for salt, copper, or full-dose medications.