Kahang

It can be told apart from other members of the B. pugnax group by the following characters: chin bar present; no complete second postorbital stripe on opercle; presence of transverse bars in caudal-fin of males; caudal-fin in males broadly lanceolate; opercle scales iridescent blue; anal-fin with reddish subdistal band and black margin; caudal-fin without dark margin; 25-28 anal-fin rays; 28-31 lateral scales; 11-12 postdorsal scales; length of pelvic fins 26.6-43.8 % SL; length of head 27.5-35.2 % SL; inter-orbital width 32.4-53.0 % HL.

Type locality is '55 miles north of Singapore, freshwater ditches, Mawai District, Johore, Malaysia', and this species has been recorded throughout much of Peninsular Malaysia and southern Thailand. Records from Borneo and Singapore appear to be in error although it may have been extirpated from the latter but as with most members of the genus a degree of confusion surrounds its identity (see 'Notes').

Prefers a dimly-lit aquarium with plenty of cover in the form of live plants, driftwood branches, terracotta pipes, plant pots, etc., arranged to form a network of nooks, crannies, and shaded spots. Surface vegetation such as Ceratopteris spp. is also appreciated and makes the fish less inclined to conceal themselves.

The reason that the paired fins are orientated vertically, as opposed to horizontally in other members of the genus, is unclear but Roberts (1989) suggest it may be an adaptation to this species' ecology, in that it displays a preference for submerged vegetation or woody structures as opposed to rocky environments. They're certainly adapted for a rea...

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.

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...

This species is occasionally marketed as 'Burmese Rainbow Barb' in the ornamental trade. others may have been exported in small numbers or as bycatch among shipments of other species. It was referred to as Mystacoleucus marginatus for decades, but that name is a simultaneous subjective synonym of M. obtusirostris following Kottelat (2013).