Apparently native to Peninsular Malaysia plus the Greater Sunda Islands of Borneo, Sumatra, and Java. Reports of this species from the Mekong, Chao Phraya, and other rivers in Indochina refer to the congener L. rubripinna (see ‘Notes’).

Type locality is ‘Indonesia: Borneo: Kalimantan Selatan: Banjarmasin’.

G. siamensis can be distinguished from congeners by the following combination of characters: possession of 5½ lateral line scales; body relatively deep, depth fits 3.2-3.4 times in SL; head large and broad, width fits 5.5-6.7 times in SL; snout not or only weakly projecting; body plain silver in colour with no dark marking on caudal peduncle.

G. ornatapinnis can be distinguished from congeners by the following combination of characters: head small; snout relatively short and blunt; caudal peduncle very deep; pectoral, pelvic, and anal fins usually reddish-orange or rose-tinted; pelvic and anal fins often with white tips; barbels completely absent.

G. lobatus can be distinguished from congeners by the following combination of characters: possession of 32-33 + 2-3 lateral line scales; 5½ scale rows between lateral line and base of dorsal-fin; body relatively slender, depth fits 3.7-4.0 times in SL; snout often projecting strongly; body plain silver in colour.

Recorded from the middle to lower Mekong river basin in southern China (Yiunnan province), Laos, Thailand, and Cambodia, plus the Chao Phraya watershed in central Thailand.

Type locality is ‘Thailand: Lam Ton Lang, a tributary of Menam Sak [Mae Nam Pa Sak; Ban Lam Thong Lang, village northwest of Pakjong’.

Native to the Mekong River drainage in Laos (where Vientiane province represents the upper limit of its range), Thailand, Cambodia, and Vietnam, and the Tapi, Chao Phraya, and Mae Klong systems in Thailand.

Type locality is ’22 kilometers upstream from Phnom Penh, Tonle Sap River, Kandal Province, Cambodia’.

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…

Probably endemic to northern India, Bangladesh, and Nepal. Records from Sri Lanka, southern India, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia, and Indonesia appear to represent other species.

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

It can be distinguished from other members of the genus by the following characters: dark longitudinal stripe on body, extending from eye to caudal peduncle; scattered tubercles present on lower jaw; 14½-16½ branched anal-fin rays; pelvic-fin long, reaching beyond anus.

It can be distinguished from other members of the genus by the following characters: lateral line absent or perforating only 2-5 scales; pharyngeal teeth hooked; body size small, not exceeding 30 mm SL; body depth less than 25 % SL; colour pattern comprising a dark bluish lateral stripe extending from the eye to the caudal peduncle, typically, but not always, forming 2-5 circular spots along its length.