Sesan

Hypsibarbus lagleri is a large cyprinid endemic to the middle Mekong basin in Laos, eastern Thailand and Cambodia. It migrates seasonally, living in larger river channels in the dry season and moving into smaller tributaries and flooded forests in the wetter months. Growing to 350 mm, it is a valued food fish, and like most of its congeners is thought to be in decline because of the damming of rivers and agriculture.

Lobocheilos melanotaenia is a grazing cyprinid from the Mekong in Laos, Thailand, Cambodia and Vietnam, plus the Dong Nai, Chao Phraya and Mae Klong. One of the most abundant species in the seasonal cyprinid migrations of the mainstream Mekong, it is available on a sporadic basis. It is told from L. rhabdoura by its deeper body, narrower mouth and a dark area in the dorsal-fin. It can be aggressive at feeding times and is not particularly tolerant of conspecifics.

Luciosoma bleekeri is a slender, pike-like cyprinid from the Mekong in Laos, Thailand, Cambodia and Vietnam, and from central and western Thailand. Subadults are traded regularly as 'apollo shark' or 'shark minnow' and it is frequently confused with L. setigerum, which has a series of black spots on the lateral line scales that this species lacks. It needs the largest private aquaria, and feeds mainly on terrestrial insects taken at the surface.

The apollo shark, Luciosoma setigerum, is a slender cyprinid found across much of Southeast Asia, from the Mekong basin to Borneo, Sumatra and Java. Subadults are traded regularly and are frequently confused with L. bleekeri, which lacks the series of black spots on the lateral line scales. A similar fish of unknown origin with no stripe on the front of the body is also common in the trade, listed as L. cf. setigerum. It needs the largest private aquaria.

The paradise fish, Macropodus opercularis, is a labyrinth fish from China south of the Yangtze, including Taiwan and Hainan, plus Vietnam and Laos. Imported to France in 1869, it was among the very first ornamental fish brought to Europe. Wild examples are uncommon in the hobby since it is farmed extensively, and xanthic, albino, red, blue and stripeless strains exist. Males are territorially aggressive, especially when breeding, and should not be housed together unless the aquarium is very large.

Incisilabeo behri is a large cyprinid native to the Mekong river system in southern China, Laos, Thailand, Vietnam and Cambodia. Growing to 450 to 550 mm, it is patently unsuitable for the home aquarium, though juveniles are available on a relatively regular basis. The only member of its genus, it is separated from Bangana by a conspicuous transverse notch across the top of the head, and migrates seasonally up the Sekong, Sesan and Srepok rivers.

Mekongina erythrospila is a large cyprinid endemic to the middle and lower Mekong River system in Laos, Thailand, Cambodia and Vietnam. It tends to inhabit medium to large river channels with fast-flowing water and rocky beds. Occasionally in the ornamental trade, it grows to 400 to 450 mm and is unsuitable for most private aquaria. It can be aggressively territorial towards conspecifics and similarly-shaped fishes.

Labeo pierrei is a large cyprinid from the Mekong river system in southern China, Laos, Thailand, Cambodia and Vietnam, and the Dong Nai in Vietnam. It grows to 800 mm and inhabits main river channels and large, deep tributaries. It migrates seasonally, moving upstream into the Sekong, Sesan and Srepok rivers at the onset of the wet season and returning downstream in the dry months.