矮外腹吸鳅

Overview

Small and relatively delicate, Hypergastromyzon humilis occasionally arrives as bycatch in wild loach shipments. It needs more restrained companion choices than many hillstream loaches, particularly where dominant relatives would monopolize food or space.

Distribution & habitat

It is known only from the Melawi basin within the Kapuas system of West Kalimantan. Genus-level habitat accounts describe shallow forest torrents with oxygenated water, rocky grazing surfaces, and fish holding position around rocks while facing the current.

Aquarium setup

Use a 45 by 30 cm footprint with varied rounded rocks over sand or gravel. Effective filtration and aeration should support the suggested turnover of 10–15 tank volumes per hour. Light promotes surface growth; avoid heavily staining fresh wood. Plants and accessible sponge surfaces add grazing area. Introduce fish only to mature water, maintain regular partial changes, and secure the lid.

Diet & feeding

Algae and associated organisms are its probable natural foods. Supplement grazing with suitable dry and vegetable-rich gel foods, using animal prey moderately. Diatoms and soft green growth are preferable to tough algae. Separately cultured rocks can renew supply, while weakened fish need uncontested food during recovery.

Behaviour & compatibility

Avoid dominant Beaufortia, Pseudogastromyzon, or Sewellia and omit nemacheilid loaches. Gentler hillstream loaches, riverine gobies, and tiny peaceful open-water cyprinids are better candidates. The genus tends to aggregate loosely, although assembling an identified group can be difficult when fish arrive only as bycatch.

Sexual dimorphism

Females are broader with a smoother snout-to-pectoral outline. Males are slimmer, with a squarer snout and more angular pectoral origins.

Notes

Seven or eight pale dorsal bars, fully joined pelvic fins, and small gill openings are useful clues. The small mouth lacking papillae distinguishes it from several broader-mouthed lookalikes.