NK1 Blue Tail Borneo Hillstream Loach（Gastromyzon ornaticauda）（SUPER RARE!!!)

NK1 Blue Tail Borneo Hillstream Loach — An Exceptionally Rare Collector’s Species

Among the rarest and most prized hillstream loaches in the hobby, the NK1 Blue Tail Borneo Hillstream Loach (Gastromyzon ornaticauda) is a breathtaking species from the pristine, fast-flowing hill streams of Borneo. What sets this fish apart is its stunning ornate patterning and the distinctive blue-tinged tail that gives it its common name — a feature that shimmers under aquarium lighting and makes it one of the most visually spectacular loaches available anywhere.

Like all hillstream loaches, G. ornaticauda has evolved a flattened, hydrodynamic body with a powerful sucker-like underside, perfectly adapted to clinging to rocks in powerful river currents. Watching one navigate the glass and rockwork of a well-set-up aquarium is a mesmerizing experience.

Care at a Glance

• Common Name: NK1 Blue Tail Borneo Hillstream Loach
• Scientific Name: Gastromyzon ornaticauda
• Origin: Borneo (fast-flowing, oxygen-rich hill streams)
• Adult Size: 2.5 – 3.8 cm (1 – 1.5 inches)
• pH: 6.6 – 7.5
• General Hardness (GH): 6 – 12
• Carbonate Hardness (KH): 1 – 2
• TDS: 100 – 300
• Temperature: 22 – 24°C (68 – 75°F) — cool, well-oxygenated water is essential
• Temperament: Peaceful herbivore; non-aggressive
• Difficulty: Easy to Moderate
• Shrimp Safe: ✅ 100% shrimp safe!

Tank & Setup Tips

The NK1 Blue Tail demands high flow, high oxygenation, and pristine water quality — conditions that replicate the fast-moving hill streams of Borneo. A powerful canister filter, powerhead, or wavemaker is essential to create the strong current they need. Temperature must remain cool (22–24°C); they will decline quickly in warm or stagnant water.

Aquascape with smooth river rocks, slate, and pebbles to provide grazing surfaces and resting spots. A mature, well-established tank with natural algae and biofilm growth on rocks and glass is strongly recommended before introducing this species. Avoid fine substrates that may interfere with their feeding.

Feeding

A dedicated herbivorous grazer. Feeds primarily on algae, biofilm, and aufwuchs growing on hard surfaces. Supplement with blanched vegetables (zucchini, cucumber, spinach), algae wafers, and spirulina-based sinking foods. A mature tank with established algae growth is critical for their long-term health and condition.

Compatible Tank Mates

Completely peaceful and 100% shrimp safe — an outstanding addition to high-flow planted or biotope tanks. Ideal companions include small, peaceful nano fish (ember tetras, chili rasboras, small danios), other hillstream loach species, and dwarf shrimp. Avoid large, boisterous, or aggressive fish.

Breeding

Breeding in captivity is considered difficult and rarely achieved. Replicating the precise conditions of their native Bornean hill streams — strong flow, cool temperatures, high oxygenation, and pristine water quality — is required for any breeding attempt.

📸 Photos are for reference only. Actual fish may vary slightly in colour and pattern — each one is uniquely beautiful!