Tan (2009) redescribed H. stephensoni and it possesses the following unique character set: sub-inferior mouth with thin barbels; five principle, 12-13 secondary pectoral fin rays (usually 12); scaleless belly; pattern of keeled scales on anterior, dorsal portion of body consisting of a single central keel in the posterior third of each scale; 43-50 lateral line…

The genus Homalopteroides was revalidated by Randall and Page (2012) and is told apart from the related Homaloptera by the following character combination: dorsal-fin origin above pelvic-fin; ≤ 60 lateral-line scales; ≤ 30 predorsal scales; oral morphology consisting of two thin and widely separated rostral barbels on each side of the mouth, thin crescent-shaped lips, the absence of any structure such as a mental pad or lobes between the lateral portions of the lower lip, and a chin that extends anterior to the lateral portions of the lower lip.

An obligate dweller of swiftly-flowing streams and headwaters containing clear, oxygen-saturated water. It often inhabits riffles and runs and is likely to show a preference for shallower zones. Substrates are generally composed of gravel, rocks, boulders or bedrock carpeted with a rich biofilm formed by algae and other micro-organisms.

Juveniles are often found in slower-moving stretches with gravel substrate and submerged tree roots. In both cases patches of aquatic plants are only occasionally pres…

Described from Kota Tinggi district, Johor state, Peninsular Malaysia but since recorded throughout much of the country as well as parts of the the Mekong river system in Thailand, Laos, Cambodia and Vietnam plus the Kapuas and several other river basins in Kalimantan Barat (West Kalimantan) province, Indonesian Borneo.

In the Kahang River, part of the Endau drainage in Jo…

Many loaches from the families Nemacheilidae, Balitoridae and Gastromyzontidae are also suitable but research your choices before purchase in order to be sure as some are excessively aggressive or otherwise competitive.

Gastromyzon spp. tend to exist in lo…

It can be distinguished from congeners by the following combination of characters: gill slit angular; presence of subopercular groove, running continuous to origin of pectoral-fin; body black with numerous, small, evenly-spaced light brown spots; head dorsum black with numerous cream spots; pectoral and pelvic fins with cream spots; caudal-fin with iridescen…

One of the more commonly-traded members of the genus and often found in mixed shipments which may contain other Gastromyzon spp. or related fishes like Beaufortia kweichowensis. These are typically labelled ‘Borneo sucker’, ‘Hong Kong pleco’, ‘butterfly loach’, etc. regardless of species.

It’s sometimes misidentified as G. punctulatus, a species not currently traded which possesses yellow finnage and a lighter-coloured, less-intensely spo…

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.

In nature G. monticola occurs sympatrically alongside Garra borneensis, Osteochilus ingeri, Gastromyzon auronigrus, G. cornusaccus, Nemacheilus olivaceus,…

Some individuals do appear very similar to G. farragus, with noticeable spotting on the head, but can usually still be told apart by examining the caudal-fin which tends to contain only a single thick, dark vertical bar in G. farragus whereas in G. ocellatus there are more often two bars, one thick, one thinner. Intermediate forms do exist though meaning identification is sometimes tricky.

This species has probably not been seen in the aquarium trade yet but has been maintained by a few private collectors.

It can be distinguished from congeners by the following combination of characters: secondary rostrum present; complete postoral pouch present; body colour brown with up to 9 thin gold stripes; head dorsum dark brown with gold reticulate pattern; subopercular groove absent; gill slit vertical; sublacrymal groove present; sno…