Hillstream loach

The hillstream loach (Gastromyzon punctulatus) is a small, specialised loach endemic to the fast-flowing streams of Borneo. It reaches only about 6.5 cm in standard length and possesses a highly flattened body and enlarged pectoral and pelvic fins that form a powerful suction cup, allowing it to cling to rocks in swift currents. Its body is patterned with small, evenly spaced pale spots over a darker base, providing excellent camouflage against the rocky substrates of its native habitat. In the aquarium, this species requires excellent water quality with high dissolved oxygen levels and moderate to strong water flow to replicate its natural torrent-stream environment. A mature tank with abundant algae-covered rocks is ideal, as it grazes on benthic algae and the associated micro-organisms that form the bulk of its diet. Supplementary foods include quality sinking wafers, blanched vegetables, and occasional live or frozen bloodworm, though protein levels should be kept moderate to avoid digestive issues. It is entirely peaceful and can be maintained in groups alongside other small, non-aggressive species that appreciate similar conditions, such as small rasboras or other hillstream loaches. The tank should have a sandy or fine gravel substrate with smooth river stones.