Red Fin Hillstream Loach

Red Fin Hillstream Loach (Pseudogastromyzon myersi) displays vivid red to orange-red fin coloration — the red fins stand out dramatically against the mottled body pattern. Pseudogastromyzon hillstream loaches are close relatives of the Gastromyzon Borneo suckers, sharing the same dramatically flattened body, suction-cup fins, and dependence on fast-flowing, algae-rich streams. The vivid fin coloration distinguishes the males during territorial displays.

Feeding & Care Tip: Live algae and biofilm growing on rocks and glass are the primary food source — see the algae requirement note above. Supplement with Hikari Mini Algae Wafers placed directly on rocks and blanched zucchini or spinach. Hikari Frozen or Freeze-Dried Baby Brine Shrimp can be offered very sparingly as an occasional protein supplement. Strong water flow and high oxygenation are as important as food for these fish.

⚠ Algae & Biofilm Requirement: Like Otocinclus catfish and Stiphodon gobies, hillstream loaches and Borneo suckers are specialized algae and biofilm grazers. They cannot survive without established live algae and biofilm growing on rocks, glass, and hardscape. A tank without significant algae growth will not support these fish regardless of supplemental feeding. Allow algae to establish thoroughly before adding hillstream loaches. Hikari Mini Algae Wafers placed directly on rocks and blanched vegetables supplement but do not replace live algae and biofilm growth.

Native to fast-flowing, clear, well-oxygenated mountain streams and rivers. The aquarium must replicate these conditions: strong filtration creating significant water movement, high oxygenation, rocky substrate and hardscape covered in established algae and biofilm, bright lighting to encourage algae growth, cool to moderate temperatures, and very clean water with low nitrates. These fish are sensitive to elevated nitrates and should never be added to immature aquariums.

Keep in small groups. Males display vivid fin coloration during territorial interactions — spectacular to observe. Compatible with other hillstream species and cool-water community fish.

A well-set-up hillstream aquarium with established algae, strong flow, and rocky hardscape brings out the best in these fish — their coloration is most vivid in optimal conditions.

Care & Ideal Parameters