This species is variable in terms of colour. Large adults may be bright green, orange or barred but are apparently capable of changing from barred to plain in just a few seconds.

These different forms have been recorded in the same natural habitats, and some individuals also possess prominent nuptial tubercules covering much of the body.

Field observations have revealed that individuals almost always position themselves facing into the flow, either along the sides, behind or under rocks, their specialised morphology (see ‘Notes’) allowing them to feed and maintain position without being swept away.

Not many fishes have been able to successfully colonise this narrow ecological niche, but syntopic species in nature include Gastromyzon extrorsus (Petagas River), G. introrsus, G. lepidogaster (Pad…