Erromyzon Hillstream Loach

Erromyzon Hillstream Loach (Erromyzon sinensis) is a beautifully patterned hillstream loach with a fine network of dark lines and spots on a pale body — similar in overall appearance to Sewellia but from a distinct genus. Previously placed in Protomyzon, the genus Erromyzon was established to accommodate this and related species. Like all hillstream loaches, this species is a specialized algae and biofilm grazer from fast-flowing mountain streams, requiring strong flow, high oxygenation, and established algae growth.

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 groups. Peaceful with other hillstream species and cool-water community fish. All standard hillstream care requirements apply.

A well-set-up hillstream aquarium with rocky hardscape, strong flow, and established algae is the key to success with all hillstream loach species.

Care & Ideal Parameters