The White Cloud Mountain Minnow, Tanichthys albonubes, is a popular aquarium fish that originally comes from mountain streams in Guangdong province, China.
There have been no confirmed records of this fish in its natural habitat in the last few decades (Fellowes et al., 2001). However, it has invaded other areas of the province, probably from aquarium stocks, so there are feral stocks in China (Fellowes et al., 2001). The situation is complicated by taxonomic arguments over whether a similar fish from Hong Kong is a separate species or a color form of this one. I haven’t managed to determine exactly what is going on here, which makes it hard to say anything useful about the conservation status of this fish in the wild.
McDowall, R. (2004) Shoot first and then ask questions: a look at aquarium fish imports and invasiveness in New Zealand New Zealand Journal of Marine and Freshwater Research, – rsnz.org