The only freshwater fish named after Hong Kong, identified recently as a new species, is already dwindling in numbers, spurring efforts by scientists to step up a breeding programme.
The Hong Kong paradise fish, Macropodus hongkongensis, found only in the city, is threatened by man-made damage to its habitat.
Researchers are now examining its genetic make-up with a view to aiding the government's breeding programme.
Last year, Chinese University obtained funding of HK$854,440 from the Environment Conservation Fund for a three-year study to see if there are genetic differences within species of fish found in different parts of Hong Kong.
Six species are being studied, including two that are of conservation concern - the Hong Kong paradise fish and the rice fish, Oryzias curvinotus.
'Animals in the ocean or on land can go anywhere they like, but this is not the case for freshwater fishes in streams,' Tsang Ling-ming, a post-doctoral fellow at the university, said.
'You can have two streams that are very close together, but the water may be from different sources; the water could be different in temperature or pH level, which means one gene pool of fish may survive in one stream but not the other.'