Despite being a wholly unsuitable aquarium subject, C. idella is often traded as such, with an albino form having been developed specifically for the ornamental market.

Individuals which have outgrown their aquarium or pond should never be released into natural waters, either, since this species has proven capable of causing serious environmental damage under a wide range of climatic conditions.

Members of the genus are characterised by possessing a particular number of dark vertical bar on each flank, and A. parallens belongs to a group of species with five or six such bars, each of which is two scales in width. Congeners sharing this pattern include A. fasciatus, A. hemispinus (in juveniles only), A. jishouensis, A. kreyenbergii, A. paradoxus, A. spinifer, A. wenchowensis, and A. wuyiensis.

No bubble nest is built and several thousand eggs simply float at the surface with both male and female remaining to defend the eggs and fry.

The eggs hatch after 24-36 hours depending on temperature and the fry are free swimming in a further 24 hours. At this point they resemble 6-7 mm long black tadpoles.

It is important to constantly feed…

Known only from a handful of localities within the Xi River (Xi Jiang) drainage in Guangxi Zhuang Autonomous Region, southern China plus the Tuoniang river system in Funing County, southeastern Yunnan province.

Type locality is ‘West River, Longzhow Xian, Guangxi Province, China’.

This species is one of several traded variously as 'butterfly loach', 'butterfly plec', 'Hong Kong plec(o)', 'Chinese hillstream loach' or simply 'hill stream loach'. In many countries it's the most common balitorid in the shops but is also often found in mixed shipments containing members of other genera.

Like all balitorids it's an obligate bottom-dweller with specialised morphology adapted to life in fast-flowing water. The paire…