The Blackline rasbora, Rasbora borapetensis, is an aquarium fish of the family Cyprinidae found in Asia from the Mekong, Chao Phraya and Mae Klong basins, and also northern Malay Peninsula. It grows to about 1.57 in (4 cm).
It has an incomplete lateral line, reaching at most to the anal fin origin – a dark brown mid-lateral stripe from gill opening to somewhat in front of the caudal fin base, not widening posteriorly and above it a second, pale stripe. There is no black pigment on the fins.
The Blackline Rasbora occurs in ponds, streams and drains, usually in slow flowing, often somewhat turbid water, from midwater level to the surface in nearly all ponds, ditches, canals and reservoir margins of 6.56 ft (2 m) depth or less. It prefers temperatures between 71.6 and 78.8Â°F (22 and 26Â°C). It feeds on zooplankton, insects, worms and crustaceans.