The Mekong basin in SE Asia is considered to be the second most diverse habitat in the world (second to the Amazon basin in SA), and is sadly one of five ecosystems under serious threat (largely due to human "development"). Many of our Cyprinid aquarium fishes come from this basin, including the dwarf loach and Boraras rasbora species.
Since 1997, there have been 1,710 new species discovered and described from this basin, and in 2011 alone there were 13 new fish species discovered. The linked article from the WWF highlights some of these more recent discoveries. http://awsassets.panda.org/downloads...t_dec_2012.pdf
As an aside, an interesting fact about the Mekong River. Maurice Kottelat, a leading ichthyologist and authority on the cyprinid fishes, recently completed more than 30 years of study on the freshwater loach fishes. His paper was published on December 28, just over two weeks ago [it is available free online:http://rmbr.nus.edu.sg/rbz/biblio/s2..._cobitidum.pdf
], and not surprisingly has resulted in an extensive revision to several species. Among them is the dwarf loach, originally described as Botia sidthimunki
, but placed (along with the near-identical species Y. nigrolineata
) by Dr. Kottelat (2004) in the genus Yasuhikotakia
. For years this species was believed to be extinct, and aquarium fish were being commercially raised in SE Asia. Dr. Kottelat subsequently determined that the lineage of these two species is very distinct from all other cyprinids, so he has erected a new genus for them, named Ambastaia
. And this [finally
] is where we come to the river name issue. Ambastaia
is the latinized form of the Greek name for a river in one of the works of Claudius Ptolemy, a Greek-Roman citizen who lived in Egypt from ca. AD 90 to ca. AD 168. About 30 or so years ago, it was finally determined that this river is actually the Mekong. As these two species occur in this river, they now reside in a genus whose name has rather an interesting history.
Read more: Dwarf Loach (Ambastaia sidthimunki ) Profile