Kok

Described from close to the village of Ban Khiri Wong, Nakhon Si Thammarat Province, southern (peninsular) Thailand but since recorded throughout much of the country, including the Chao Phraya and Mekong river systems. It's also known from Peninsular Malaysia and parts of the Mekong basin in Laos, Cambodia and Vietnam. Rainboth (1996) considered it 'probably the commonest member of the genus in the Mekong' and in a 2008 study of balitorid habitats in centra...

Known from various parts of the middle and upper Mekong river basins with record existing from the Nam Tha, Nam Ou, Nam Khan, Nam Lik, Nam Ngum and Nam Mang tributary systems in Laos, the Nam Noeua (a tributary of Nam Ou) in Vietnam, and the Mae Nam Kok in Thailand. Occurrences in the Chao Phraya drainage in central Thailand most likely refer to the congener R. chiengmaiensis.

It can be distinguished from congeners by its small adult size and presence of a single solid dark midlateral stripe on the body, above which is a series of dark blotches forming a second stripe. In the similar but larger, T. schalleri the upper stripe is more variable depending on the mood of the fish, sometimes fading entirely.

Known from the middle Mekong basin in Laos and Thailand, including the Mun tributary drainage on the Khorat Plateau in northeastern Thailand, plus the Chao Phraya and Mae Klong watersheds in central and western Thailand, respectively. In the Mekong system it may also occur further upriver in Yunnan province, China, while the Khone Falls in Laos appear to represent its downstream limit.