Delicate Blue-eye Rainbowfish (Pseudomugil tenellus)

Delicate Blue-eye Rainbowfish (Pseudomugil tenellus) — Ethereal Beauty for the Nano Aquarium

The Delicate Blue-eye Rainbowfish (Pseudomugil tenellus) is a rare and exquisite nano fish from the shallow, sun-dappled streams and wetlands of northern Australia. True to its name, this delicate species captivates with its translucent, silvery body, vivid electric blue eyes, and the males’ ornate, elongated fins edged in soft yellow and white — a combination of subtlety and brilliance that makes it one of the most refined and sought-after nano rainbowfish in the hobby.

Subtle Elegance, Extraordinary Detail

At just 3–4 cm in length, the Delicate Blue-eye Rainbowfish is among the smallest of the Pseudomugil genus — but its beauty is anything but understated. Males in breeding condition display their ornate fins in a constant, shimmering courtship display, their electric blue eyes catching the light with every turn. In a well-planted nano aquarium with warm, dappled lighting, a group of Delicate Blue-eyes creates an ethereal, almost otherworldly display of movement and colour.

Care Profile

• Scientific Name: Pseudomugil tenellus
• Origin: Northern Australia — shallow streams, wetlands, and seasonal pools
• Size: Up to 3–4 cm
• Temperament: Peaceful; best kept in mixed-sex groups of 8 or more to encourage natural display behaviour
• Diet: Omnivore — accepts micro pellets, baby brine shrimp, daphnia, micro worms, and finely crushed flake food
• Water Temperature: 24–30°C (prefers warmer water than many other Pseudomugil species)
• pH: 6.5–7.5 (adaptable; prefers soft to moderately hard water)
• Tank Size: Suitable from 40L upward; ideal for nano tanks of 40–80L
• Note: A delicate species — keep with very peaceful, similarly sized tankmates and maintain excellent water quality; avoid boisterous or fin-nipping species

Aquascape Compatibility

The Delicate Blue-eye Rainbowfish thrives in heavily planted nano aquariums with fine-leaved plants, floating cover, and gentle water movement that replicates its shallow Australian wetland habitat. It pairs beautifully with other peaceful nano fish — small rasboras, micro tetras, and dwarf shrimp — in a lush, naturalistic community setup. Its translucent body and vivid blue eyes create a hauntingly beautiful effect against green planting and warm aquarium lighting.

Rare, refined, and breathtakingly delicate — the Delicate Blue-eye Rainbowfish is the nano jewel that brings the quiet beauty of the Australian wetlands to your planted aquarium.