Considered synonymous with the congener L. laubuca for a number of years, thus reports of that species from anywhere in Indochina actually refer to the current concept of L. siamensis.

Given the distribution of L. siamensis, it seems likely that many of the fish entering the aquarium trade are also this species and not L. laubuca. The two species can be distinguished by…

Known from the Pahang River system in southern Peninsular Malaysia, and the Greater Sunda Islands of Sumatra and Borneo. On the latter records exist from the Kapuas, Barito, and Mahakam watersheds in Kalimantan, the Indonesian portion of the island

Type locality is ‘Pangabuang, Lampong Province, Sumatra, Indonesia’.

H. wetmorei is distinguished from congeners by the following combination of characters: upper body reddish brown; robust body, not compressed; usually 4½ scale rows between lateral line and dorsal-fin origin; 8-12 rakers on first gill arch; 7-9 predorsal scales; 14 circumpeduncular scale rows; usually two scale rows separating vent and anal-fin; <29 lateral line scales; 9-14 serrations on the spinous dorsal-fin ray; distance between distal serrae on posterior margin of last unbranched dorsal-fin ray much greater than the width of their bases.

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 was originally named Nemacheilus masyae but following ICZN rules the spelling was later corrected to N. masyai because it’s named after a man. It can be distinguished from the majority of congeners by body patterning comprising 14-18 short, dark vertical bars on each flank, 12-17 saddle-like markings running along the dorsal surface, a dark spot on the caudal peduncle at the termination of the lateral line and a dark blotch in the lower half of the first few dorsal-fin rays.

The distribution records for this species are somewhat confusing. It was described from the confluence of the Lamatang and Enim rivers, Palambang Province, Sumatra and has since been recorded from Thailand (Chao Phraya River), Peninsular Malaysia (Pahang River) plus the islands of Java (Solo River) and Borneo (Kapuas and Barito rivers).

Type locality is given as ‘Kuala Tahan, Pahang (King George V National Park)’ which corresponds to the village of Kuala Tahan in Pahang state, central Peninsular Malaysia.

The settlement is located at the confluence of the Tahan and Tembiling Rivers which form part of the Pahang river basin, while the national park was re…

It can be distinguished from congeners by the following combination of characters: 61-68 scales in the lateral series; a small, well-defined, sometimes ocellated black spot on the shoulder and another in the centre of the caudal peduncle; body without longitudinal stripes formed by spots on scales; caudal fin uniformly dusky or colourless, lobes without stripes or black margins.

Recorded from numerous river basins in Vietnam, Cambodia, Laos, Thailand, and Peninsular Malaysia, including the Mekong, Chao Phraya, Mae Khlong, Chanthaburi, Tapi, Golok, Terengganu, Pahang, Endau, and Muar.

Type locality is ‘Kratt, southeastern Siam’, which corresponds to modern-day Trat Province, Thailand.

Aggressively territorial and incompatible with other fishes in all but the largest public installations and even then may attack its tankmates.

It’s also one of few freshwater fishes that appear unafraid of humans meaning care must be exercised when performing maintenance.