Bassac basin

Bagrichthys obscurus is a bagrid catfish from the Chao Phraya, Bang Pakong and Mekong watersheds in Thailand, Cambodia and Vietnam. One of the lancers, named for the extended dorsal spine in several members of the genus, it has a uniformly brown body with no pale stripe or blotches, a small mouth and a relatively short dorsal spine. It inhabits large, turbid rivers with slow flow, and is shy, nocturnal and territorial towards other bottom-dwellers.

Hemibagrus spilopterus is a bagrid catfish from the Mekong and several other river systems in Laos, Vietnam, Cambodia and Thailand. Relatively common in the ornamental trade, it has been widely misidentified as H. nemurus, a Javan species that may never have been exported for aquaria. Given its size of up to 500 mm SL, its aggressive nature and a lifespan of several decades, it shouldn't be considered a home aquarium subject in all but the most exceptional circumstances.

Amblyrhynchichthys micracanthus is a riverine cyprinid from the Mekong catchment in Laos, Thailand, Cambodia and Vietnam, and the Chao Phraya system. It moves into inundated forest during the wet season, and wild fish feed on periphyton, plankton and benthic algae. Older records of A. truncatus from mainland Indochina all refer to this species, which has a straighter snout profile, a shorter dorsal-fin spine and fewer gill rakers.