Temburong basin

Gastromyzon aeroides is a hillstream loach endemic to northern Borneo, recorded from western Sabah in Malaysia and the Temburong basin in Brunei. The dorsal, caudal and anal fins are blue in life, and the plain brown body separates it from the other two species in the G. punctulatus group. Like its congeners it needs swift, clean, well-oxygenated water.

Gastromyzon lepidogaster is a hillstream loach from northern Borneo and the most widely-distributed member of the genus. It occurs in Sabah, Brunei and East Kalimantan. Colour is variable: large adults may be bright green, orange or barred, and can apparently change from barred to plain in a few seconds. It is occasionally available in the trade, where the orange form is particularly sought after.