Erromyzon spp. are obligate dwellers of shallow, fast-flowing, highly-oxygenated headwaters/minor tributaries characterised by stretches of riffles and runs broken up by pools or cascades in some cases. Substrates are normally composed of smaller rocks, sand and gravel with jumbles of boulders, and while riparian/stream-side vegetation and patches of submerged leaf litter are common features aquatic plants aren’t usually present.

At time of writing there exist 18 recognised members of the genus though only B. kweichowensis is well-known in the trade with B. szechuanensis unlikely to have been exported. According to Chen, Huang and Yang (2009) it can be distinguished from similar congeners by the following suite of characters: 1 branched and 17-20 simple pectoral-fin rays…

This fish may only have been exported for aquaria on a single occasion to date. It exhibits characters reminiscent of both L. alkaia and L. guntea, and has been referred to as L. cf. guntea) but is most likely an undescribed species (Havird, pers. comm.).

Tan (2009) redescribed H. stephensoni and it possesses the following unique character set: sub-inferior mouth with thin barbels; five principle, 12-13 secondary pectoral fin rays (usually 12); scaleless belly; pattern of keeled scales on anterior, dorsal portion of body consisting of a single central keel in the posterior third of each scale; 43-50 lateral line…

This fish has only been traded on a handful of occasions to date. It's been referred to as Lepidocephalichthys cf. hasselti and Lepidocephalus cf. thermalis but appears to be an undescribed member of the former genus. Following a…

This species is not traded often but may be available occasionally bycatch among shipments of other species. It can be told apart from congeners most easily by the following combination of characters: truncate caudal-fin; scaleless patch on top of head; caudal-fin with reticulated patterning, sometimes appearing as a series of thin vertical bars; body reddish brown with darker markings; 3-7 predorsal and 3-6 postdorsal thin, transverse dark bars running across the dorsal surface; relatively deep…

This is one of the most frequently-traded members of the group and is an excellent choice for those new to keeping loaches. It’s distinguishable from congeners by a combination of characters including: rounded/truncate caudal-fin; a scaleless patch on top of the head; relatively large adult size; flanks with spotted patterning in females and a solid…

This species is not traded often but is occasionally available as bycatch among shipments of other species. It can be told apart from congeners most easily by the prominent, dorsally-orientated, roughly semi-circular lamina circularis in males, a feature unique within the genus. Other distinguishing characters include a combination of: forked caudal-fin; relatively small adult size; dark <-shaped mark at the base of the caudal-fin; a black spot at the base of branched caudal-fin rays 3-5.

This is one of the most frequently-traded members of the genus and is an excellent choice for those new to keeping loaches.

It’s distinguishable from congeners by a combination of characters including: relatively large adult size (to at least 80 mm SL); rounded/truncate caud…

Sand-dwelling loaches from the families Botiidae, Cobitidae and Nemacheilidae are also suitable but proper research is essential as some can be excessively territorial or otherwise aggressive.

A community based around fishes from its natural waters could include species such as Badis badis,…