Dawkinsia

Dawkinsia arulius is a cyprinid from Karnataka, southwestern India, apparently now restricted to the upper Cauvery and the Tungabhadra headwaters. Adults have three large, diffuse dark markings on the body. It appears extirpated at its type locality, most likely because of the Krishna Raja Sagara dam upstream, and the fish traded as 'arulius barb' is often the related D. tambraparniei, in which males have filamentous dorsal-fin rays.

The mascara barb, Dawkinsia assimilis, is a cyprinid from the Netravati, Chalakudy and Kallada basins of Karnataka and Kerala, India. The caudal-fin lobes are tipped with a black band about as wide as the eye, faint or absent in Kallada fish. Misidentified in the past as Puntius mahecola, it still appears on trade lists as 'mahecola barb', and some populations might represent distinct species.

Dawkinsia exclamatio is a cyprinid from the Kallada River in southern Kerala, India, and may be endemic to that river system. Rare in the hobby, it occasionally arrives as bycatch among similar-looking species such as D. assimilis. Two black blotches on each flank set it apart from the rest of the group, but there is a case that it is a natural hybrid between D. assimilis and a D. arulius-like fish found with it at its type locality.

The filament barb, Dawkinsia filamentosa, is a cyprinid endemic to the Western Ghats region of southern India, in Kerala, Tamil Nadu and Karnataka. Adult males and some females develop filament-like extensions to the branched dorsal-fin rays. Most common in lowland coastal floodplains, it occurs in fresh and brackish water, and it also appears on trade lists as 'blackspot barb' or 'mahecola barb'.

Dawkinsia rohani is a cyprinid known only from Kanyakumari District, Tamil Nadu state, at the southern tip of the Indian peninsula. A single black club-shaped blotch running back to the caudal-fin base, with no other body markings in front of it, separates it from congeners. Habitat data are lacking, but it is a pelagic, riverine species and apparently most common in hill streams.

Dawkinsia rubrotinctus is a cyprinid from southern India, considered widespread throughout the Cauvery drainage in Karnataka, Kerala and Tamil Nadu. It may have appeared in the trade under the misapplied names Puntius arulius and P. tambraparniei. Three small, well-defined dark body markings separate it from D. arulius, D. srilankensis and D. tambraparniei, in which the markings are larger and more diffuse.

The 'arulius' barb, Dawkinsia tambraparniei, is a cyprinid possibly restricted to the middle Tambraparni River basin in Tamil Nadu, southern India. Described as a subspecies of D. arulius, it appears in most earlier aquarium literature as Puntius arulius or 'arulius barb' and is often still traded as such, although D. arulius is quite different-looking and rarely exported. Many fish in the trade are likely to have been bred commercially.