Borneo Sucker Loach

Borneo Sucker Loach (Gastromyzon sp.) is a Gastromyzon species — a Borneo sucker loach with the characteristic flat, wide body and suction-cup fins adapted for clinging to rocks in fast-flowing streams. The exact species is unconfirmed in this listing. Gastromyzon Borneo suckers are hillstream loaches endemic to the fast-flowing streams of Borneo — among the most spectacular and alien-looking freshwater fish available. The body is extremely flattened with suction-cup pectoral and pelvic fins that allow these fish to cling to rocks in torrential flow.

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 can be territorial but are peaceful with other species. Compatible with other hillstream species, cool-water danios, and White Cloud Mountain Minnows. Strong flow, high oxygenation, and established algae on rocks are the non-negotiable requirements.

The Borneo sucker lifestyle is extraordinary — these fish spend their lives pressed flat against rocks in powerful current, rasping algae and biofilm with specialized mouthparts. In a well-set-up hillstream aquarium they are active, fascinating to observe, and surprisingly personable.

Care & Ideal Parameters