Thu Bon

Hypsibarbus wetmorei is a cyprinid widespread in mainland Southeast Asia, from the lower Mekong basin south to the Pahang River in Malaysia. Its orange to red pectoral, pelvic and anal fins separate it from the very similar H. vernayi (yellow), and yellow-finned fish traded as H. wetmorei or 'lemon fin barb' appear likely to be that species. It prefers flowing water with abundant riparian vegetation and grows to 250 mm.

The black paradise fish, Macropodus spechti, is a labyrinth fish from central Vietnam, known with certainty from the Thu Bồn and Hương river systems. Its name is frequently misapplied to the similar-looking M. erythropterus, easily identified by reddish pigmentation in the dorsal, anal and caudal fins. Older literature sometimes refers to it as M. concolor. Relatively peaceful unless breeding, it is kept in pairs.

Sewellia albisuera is a hillstream loach known only from a handful of localities in the Thu Bon river system, Quang Nam province, central Vietnam. It is very rarely traded but resembles S. sp. 'SEW01', from which it differs in its network of irregular dark reticulations (many small light spots in SEW01). It inhabits shallow, fast-flowing, highly-oxygenated headwaters and tributaries, and the type locality is apparently suffering from pollution.

The tiger hillstream loach, Sewellia lineolata, is a gastromyzontid loach from fast-flowing headwaters in Vietnam and on the Mekong in Laos. Three to five dark stripes on the body make it difficult to confuse with any other member of the genus. The water must be clean, fast-flowing and well-oxygenated, and Sewellia species are arguably the easiest of all loaches to breed in aquaria.

Garra fuliginosa is a cyprinid from the Mekong basin in Thailand, Laos, Vietnam and Cambodia, and the Chao Phraya and Mae Klong in Thailand. It tends to inhabit swiftly-flowing headwaters and tributaries with clear, oxygen-saturated water. Like other Garra it has a lower lip modified to form a mental adhesive disc for clinging to surfaces. The body is dark with random lighter scales.