Endemic to the Ganges and Brahmaputra river basins and thus occurs in northern India, Nepal and Bangladesh. Type locality is ‘the Yamuna River, and northern rivers of Behar and Bengal’.

The distribution of the genus as a whole is interesting because these fish occupy the area that geographically separates Indian and Southeast Asia barbs and it has been theorised that they may represent an evolutionary ‘link’ species…

An assortment of undescribed Oreichthys spp. from India, Myanmar and Thailand are currently traded as O. cosuatis. It can be distinguished from other described members of the genus by lacking a black blotch on the caudal peduncle, plus the following combination of characters: 2-3 perforated scales in lateral line; ½6½ between pelvic-fin origin and dorsal midline; presence of dark stripe in centre of anal-fin, forming a triangular blotch in adult individuals; dorsal-fin with whitish tip and broad, black, subdistal margin in the upper portion of the fin; 11-13 rows…

This species is uncommon in the aquarium trade which is a little surprising given its huge natural range. Different populations can vary in colour pattern to an extent though all share the defining aspects given by Hamilton, comprising a diffuse yellow-golden marking on the operculum plus a dark spot on the caudal peduncle. The latter is usually surrounded by a variably-sized golden-yellow margin, and the dorsal-fin often contains irregular dark spots and streaks, these sometimes forming a longitudinal band.

In the Barak River drainage, which flows through the north-east Indian states of Nagaland and Assam before bifurcating at the Bangladesh border, symaptric species include Barilius bakeri, B. barna, B. bendelisis, B. dogarsinghi, Laubuca laubuca, Esomus danricus, Devario aequipinnatus, D. annandalei, D. devario, Rasbora daniconius, R. rasbora,…

X. cancila is often seen referred to as ‘freshwater garfish’, and although it does superficially resemble the true gars of the family Lepisosteidae, it’s actually a member of the Belonidae, or needlefishes, the majority of which are marine or estuarine in existence.

There are currently just two species in the genus although the probable existence of a third member has been noted by Roberts (1989) among oth…

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.

Traded under various names including ‘mottled’, ‘eyepot’, ‘sand’ and ‘striped’ loach. It’s perhaps one of the better choices for those new to keeping nemacheilids being relatively hardy, peaceful and exhibiting some quirky behavioural traits. The characteristic ocellus, a dark marking at the top of the caudal peduncle that resembles an eye, is thought to have some function in predator distraction and is normally more intense in younger specimens.

This species’ name has been widely misapplied in the aquarium trade and hobbyist literature, most often in reference to the Southeast Asian species C. ornata, but unlike its relative is in fact very rarely exported for ornamental purposes although its is fished and cultured for food in India.

It can be told apart from C. ornata by possessing fe…

Ecological studies have revealed this species to be more of a generalist than its chiefly insectivorous congeners.

Aquatic and terrestrial insects form a significant proportion of the diet, but substantial amounts of filamentous algae and diatoms are consumed with water mites, fish scales, isopods, nematodes and detritus also taken occasionally.

In the aquarium it’s largely unfu…

This species is also referred to by the alternative vernacular name of 'noble gourami' and is currently the only recognised member of the genus Ctenops. It is usually regarded as being very difficult to keep whereas in reality it is quite adaptable once acclimatised but appears to react poorly to the export and shipping process meaning it is often seen on sale in poor condition and susceptible to or already infested with secondary health issues such as Oödinium, to which it appear…