Slender Blue-eye

Pseudomugil tenellus is among the more widely distributed blue-eyes, found across tropical northern Australia and portions of Papua New Guinea in shallow, well-vegetated streams, swamps, and seasonal floodplain pools. It is a slender, graceful species as befits its name (tenellus = tender, delicate), with a pale semi-transparent body that allows the vivid iridescent blue eyes to stand out dramatically. Males develop yellow to orange fin margins and subtle dark fin markings during courtship.

This species is moderately adaptable and tolerates a wider range of conditions than some Pseudomugil, including slightly acidic to alkaline water across its broad range. It is better suited to cooler to moderately warm conditions than some New Guinean blue-eyes. A planted aquarium with gentle flow and dense cover — floating plants, fine-leaved stem plants — provides ideal conditions.

Pseudomugil tenellus is periodically available from specialist breeders and Australian native fish enthusiasts. It breeds readily in a well-maintained planted aquarium, depositing adhesive eggs on fine vegetation or spawning mops. Fry are small but not especially fragile.

Water: pH 6.5–7.5, temperature 22–28°C, soft to moderately hard; tolerant but prefers stable, clean conditions. Tank: Minimum 40 L; planted with dense fine-leaved vegetation and floating plants; gentle flow. Feeding: Micro-pellets, fine flake; regular baby brine shrimp and micro-worms. Breeding: Egg scatterer on fine vegetation; fry small but manageable; infusoria for first week. Compatibility: Peaceful nano species; excellent with dwarf rasboras, micro-tetras, and dwarf shrimp.