Taxonomy & naming
Day described the species in 1865 as Barilius bakeri, from Mundikyum near Cochin. It is now placed in Opsarius, with the authority in parentheses. Opsarius is a genus of stream-dwelling cyprinids of South and Southeast Asia, formerly included in Barilius, with an elongate body and a wide mouth suited to taking insects at the surface.
Morphology
A slender, silvery stream fish with a wide mouth. FishBase gives a maximum of 6 in TL; colour has not been described in the sources the atlas uses.
Habitat
It lives in small mountain streams of Kerala and the southern Western Ghats; FishBase lists the range as the Western Ghats in Kerala. Water parameters have not been published.
Feeding
Opsarius are active surface and midwater predators of insects that fall on the water, taking small invertebrates and sometimes small fish. The diet of this species has not been described separately.
Mating
Mating behaviour has not been described.
Breeding
Captive breeding has not been documented.
In the aquarium
Keep it in a long tank with strong flow, high oxygen, cool to moderate temperatures and a tight lid, since these fish jump. Keep a group, and give small live, frozen and floating foods. Care notes come from the genus.
Conservation
The IUCN Red List category is Least Concern, assessed in 2011. Threats have not been described.