Red Devil Borneo Hillstream Loach（Gastromyzon Russulus）（SUPER RARE!!!)

Red Devil Borneo Hillstream Loach — The Rarest of the Rare

Fierce in name, stunning in appearance, and extraordinarily rare in the trade, the Red Devil Borneo Hillstream Loach (Gastromyzon russulus) is the crown jewel of the hillstream loach world. Endemic to the pristine, fast-flowing hill streams of Borneo, this exceptional species is distinguished by its vivid reddish-orange suffusion and intricate body patterning — a combination that makes it one of the most visually dramatic and sought-after loaches in existence.

Like all Gastromyzon species, the Red Devil has evolved a perfectly flattened, hydrodynamic body with a powerful sucker-like underside, allowing it to cling effortlessly to rocks in powerful river currents. In the aquarium, it glides across glass and rockwork with an almost supernatural grace — a living masterpiece of evolutionary design.

Care at a Glance

• Common Name: Red Devil Borneo Hillstream Loach
• Scientific Name: Gastromyzon russulus
• Origin: Borneo (pristine, fast-flowing 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, highly oxygenated water is non-negotiable
• Temperament: Peaceful herbivore; non-aggressive
• Difficulty: Easy to Moderate
• Shrimp Safe: ✅ 100% shrimp safe!

Tank & Setup Tips

The Red Devil Hillstream Loach demands exceptional water quality, strong flow, and high oxygenation — conditions that mirror the fast-moving, crystal-clear hill streams of Borneo. A powerful canister filter, powerhead, or wavemaker is essential. Temperature must be maintained cool (22–24°C); warm or stagnant water is fatal to this species.

Aquascape with smooth river rocks, slate, and pebbles to provide abundant grazing surfaces and resting spots. A mature, well-established tank with natural algae and biofilm growth is strongly recommended before introducing this rare species. This is a fish that rewards the prepared and dedicated aquarist.

Feeding

A specialist 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 well-established algae and biofilm growth is critical — do not introduce this species to a new or uncycled aquarium.

Compatible Tank Mates

Completely peaceful and 100% shrimp safe. 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 that may stress this rare and sensitive species.

Breeding

Breeding in captivity is considered very difficult and rarely documented. 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. A true achievement for the specialist aquarist.

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