H. malcolmi is distinguished from congeners by the following combination of characters: 12-17 (usually 14-15) rakers on first gill arch; usually 16 circumpeduncular scale rows; less than 30 lateral line scales; some branched lateral line canals, but branching not extensive, median portion of dorsal-fin dark.

In the Mekong, it has been observed to migrate upstream from Phnom Penh to Khone Falls between November and February, returning downstream between May and August. The downstream migration ends in the Mekong delta area in Vietnam, where the fish remain until the floods reach their peak in October and November. These lower Mekong migrations mostly comprise juveniles and sub-adults, whereas above Khone Falls…

It can be distinguished from congeners by possessing one or two pairs of barbels, a black blotch at the base of the caudal-fin, and rows of dark spots along the lateral scale rows.

Members of Cyclocheilichthys are characterised by possessing a serrated dorsal fin spine, 9 branched pelvic fin rays, a conical snout, small, subterminal…

Given its wide natural range it seems logical that this species is or has been available in the aquarium trade, although its correct name may never have been applied.

It is told apart from congeners by the following combination of characters: two pairs of barbels; a continuous midlateral stripe from the tip of the snout to the base of the caudal-fin, with a conspicuous small blotch at the posterior extremity, faintly marked on the caudal-fin; a faint mark between the anus and the anal-fin origin in juveniles; a narrow mouth.

Appears to have a disjunct range with records from Pahang state in central Peninsular Malaysia, plus the Mae Klong and Chao Phraya river systems in Thailand, but it has not been recorded in Peninsular Thailand.

Type locality is ‘Pahang River, Kuala Tembeling, eastern slope of Sangka Dua Pass, Malaysia, elevation about 2000 feet’.

This species is not collected for the aquarium trade at time of writing.

In contrast to other members of the genus older juvenile and adult individuals lack dark markings on the body while the jaw is more pronounced.

There is considerable confusion surrounding the identity of B. bagarius with its name having been widely applied to a relatively small species that is said to reach only 200 mm SL and considered to be common in northern India and much of Indochina.

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.

G. filamentosa has appeared in the ornamental trade but is evidently delicate and therefore recommended only to experienced aquarists.

It can be told apart from congeners by the following combination of characters: possession of filamentous dorsal and anal-fin rays in males; body transparent to translucent yellowish-brown colour in life; absence of a highly-extended second anal-fin spine; absence of carmine-red pigmentation in the dorsal, anal an…

This species is a near-exclusive inhabitant of the upper water column and appreciates surface cover in the form of floating or overhanging vegetation.

Other décor is relatively unimportant but can consist of a sandy substrate with leaf litter plus some large driftwood branches and twisted roots.

Plants which can grow rooted in sand can al…