Hillstream Loach

The Hillstream Loach, also known as the Reticulated Hillstream Loach or Butterfly Loach, is a fascinating and unique freshwater fish adapted to life in fast-flowing streams. Native to Southeast Asia, these loaches have a flattened, streamlined body shape with beautiful reticulated patterns in brown, tan, and cream. They possess a sucker-like mouth that allows them to cling to rocks in strong currents while grazing on algae. Hillstream Loaches are peaceful, algae-eating specialists that add interest and functionality to appropriate setups. They require cooler temperatures and strong water flow, making them ideal for unheated tanks with compatible cool-water species.

Care Requirements

Tank Setup

Hillstream Loaches need specialized conditions mimicking fast-flowing streams:

• Minimum 30 gallons (40+ recommended)
• Strong water flow - multiple powerheads needed
• Smooth, rounded river rocks - for grazing and clinging
• Cooler temperatures - one of the few tropical fish preferring cooler water
• High oxygenation (surface agitation from flow)
• Smooth gravel or sand substrate
• Heater set low or no heater (maintain 65-75°F)
• Bright lighting to promote algae growth

Critical: They absolutely require strong current and cooler water. Standard tropical setups will stress them.

Water Quality

• Temperature: 65-75°F (18-24°C) - cooler than most tropical fish
• pH: 6.5-7.5 (neutral preferred)
• Water Hardness: Soft to moderate (2-12 dGH)
• Ammonia/Nitrite: 0 ppm
• Nitrate: <20 ppm
• Oxygen: High oxygen levels essential

Maintenance:

• Weekly 25% water changes
• Strong filtration and water flow mandatory
• Maintain cooler temperatures
• Ensure high oxygenation

Feeding

Hillstream Loaches are specialized algae and biofilm grazers:

• Primary: Algae growing on rocks and glass
• Algae wafers: Sinking varieties
• Vegetables: Blanched cucumber, zucchini, spinach
• Biofilm: Natural growth on surfaces
• Spirulina-based foods

Feeding Schedule: They graze constantly on available algae. Supplement with algae wafers and vegetables if natural algae is insufficient.

Important: Ensure adequate algae growth or daily supplemental feeding. They can starve in sterile tanks.

Behavior & Compatibility

Hillstream Loaches are peaceful and unique:

• Good Tank Mates:

  • Cool-water fish: White Cloud Mountain Minnows, Zebra Danios
  • Pearl Danios
  • Cool-water tolerant tetras (Neon)
  • Corydoras (cooler water varieties)
  • Amano shrimp
  • Nerite snails

• Avoid Housing With:

  • Warm water fish (most tropical species)
  • Large aggressive fish
  • Fin-nippers
  • Competing algae eaters (Otocinclus, other loaches)

Behavior: They cling to rocks and glass in the current, grazing on algae. Very active and entertaining to watch.

Specialized Care

Hillstream Loaches have unique requirements:

• Temperature: Keep below 75°F for long-term health
• Flow: Strong current throughout the tank
• Surface area: Lots of smooth rocks for grazing
• Oxygen: High oxygen saturation from strong flow

Jumping

Hillstream Loaches can jump:

• Recommended: Tight-fitting lid
• They may jump during water changes or when startled

Health Considerations

Hillstream Loaches can be sensitive:

• Starvation: Most common issue - ensure adequate algae
• Heat stress: Temperatures above 75°F cause stress
• Poor flow: Insufficient current weakens them
• Ich: Quarantine new fish

Prevention: Maintain cool temperatures, strong flow, adequate algae growth, and stable parameters.