Mesonoemacheilus

Mesonoemacheilus guentheri is a loach from the Western Ghats of southern India, described from the Nilgiri Hills and since recorded in Kerala. Outside India it is most often seen as bycatch among shipments of M. triangularis. It is often confused with M. herrei, since both have rows of yellowish, dark-edged spots, but its spots are rounded where those of M. herrei are 'Y' or 'V' shaped. Some aquarists report it as peaceful and others as territorial and aggressive.

Mesonoemacheilus herrei is a loach from the Anaimalai Hills of the Western Ghats in Tamil Nadu, southern India. It is unclear if it has ever been exported outside India, though the odd specimen may turn up among shipments of M. guentheri or M. triangularis. It was earlier considered synonymous with M. guentheri and shares its rows of yellowish, dark-edged spots, which in this species are 'Y' or 'V' shaped.

Mesonoemacheilus petrubanarescui is a loach from the Netravati and Kabini river basins in the Western Ghats of southern India. It may be endemic to these two drainages. The dorsal surface carries 7-8 dark, saddle-shaped markings and the flanks a varying number of broken bars. It is unclear if it has been traded outside India, but it may turn up among shipments of M. guentheri or M. triangularis.

The zodiac loach, Mesonoemacheilus triangularis, is a loach from the Western Ghats of Kerala and Tamil Nadu in southern India. Also called the 'Batik loach', it is relatively common in the aquarium trade. Pale, black-edged saddles along the back and a similar set of bars from the belly set it apart from its congeners. Aquarists differ on its temperament, some finding it peaceful and others territorial and aggressive.