Reticulated Hillstream Loach

Reticulated Hillstream Loach (Sewellia lineolata) is the most widely kept Sewellia species — the body displays a fine, precise network of dark lines on a pale background creating an intricate reticulated pattern across the entire flattened body. Under good lighting the pattern has an almost geometric, mandala-like quality. Sewellia lineolata is one of the few hillstream loaches that has been successfully bred in captivity. Sewellia hillstream loaches share the same extraordinarily flattened body, suction-cup fins, and algae-grazing lifestyle as all hillstream loaches. The genus is native to fast-flowing streams of Vietnam and southern China and is highly regarded among hillstream loach enthusiasts.

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 of three or more. Males are territorial with each other but peaceful with other species. Strong flow, established algae and biofilm on rocks, and very clean water are essential.

Sewellia species are among the most visually complex hillstream loaches available — the intricate body patterns reward close observation. In a well-set-up hillstream aquarium they are active, visible, and genuinely captivating.

Care & Ideal Parameters