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…

This rarely-traded species is a member of the H. ocellata ‘group’ of closely-related congeners, an assemblage which currently comprises H. ocellata, H. bilineata, H. confuzona, H. orthogoniata, H. ogilviei and H. parclitella. Following Tan and Ng (2005) these share possession of a colour pattern with reddish tints and dark brown head markings, elongate head, slightly compressed body, 61-77 lateral line scales and dorsal-fin origin placed in advance of pelvic-fin origin.

Adult patterning of the different geographical forms can vary considerably though young specimens all possess 5 solid dark bars on each flank and are often confused with those species exhibiting a similar juvenile pattern, particularly B. kubotai. However the horizontal dark bars on the flanks in B. kubotai typically split at quite a young age and/or develop horizontally-orientated ‘peaks’ whereas those in B. histrionica remain solid for longer and the central bar usually has a pale spot at the top so forms a ‘y’ shape.

According to Kottelat (1990) the chief distinguishing characters for the genus are: possession of 9-18½ branched dorsal-fin rays; colour pattern without black basal caudal bar, but with an ocellus at upper base of caudal-fin; upper lip with or without several rows of papillae; lower lip with a broad median interruption and a widened, papillated pad on each side.

There are currently three species which look almost identical and are most easily separated by collection details since their ranges do not overlap in nature; C. chagunio is endemic to the Ganges and Brahmaputra drainages and C. nicholsi to the Ayeyarwady/Irrawaddy.

This species is also referred to as ‘Asian knifefish’ or ‘ghost knifefish’ in the aquarium trade in the aquarium trade but arguably has no place in the ornamental hobby given its adult size and specialised requirements.

It is sometimes confused with the African species Xenomystus nigri but is easily told apart by its larger adult size and presence (vs. absence) of a dorsal fin.

B. ruber is among the better known Badis species in the aquarium hobby with trade names including ‘Burmese badis’ and ‘red badis’.

It was referred as Badis badis burmicanus for a number of years and will be seen labelled as such in older literature.

Among congeners it is most easily confused with…

Interestingly some observations suggest that the character of the highest-ranked, or alpha, fish appears to affect that of the whole group though it must be said that scientific studies of botiid loach behaviour are virtually non-existent. It certainly seems that they display a degree of ‘personality’ with some specimens being naturally bolder/more aggressive than others. The alpha is normally the largest specimen within the group and often female.

Sound also appears to be an important factor in communication since these loaches are able…

The genus Danio contains only the type species, D. dangila, separated on the basis of its larger size and the shape of the caudal-fin, which in adults is only slightly emarginate or even truncate in shape, a feature it shares only with Tinca tinca (the common tench) among other cyprinids.

The remaining species, of which B. rerio is thought to be the most ancient, are included in the revalidated genus Brachydanio Weber & de Beaufort, 1916.