Slender rasbora

The black-line rasbora or slender rasbora (Rasbora daniconius) (called darka at Rangpur), is a species of ray-finned fish in the genus cyprinid family. It is found in rivers of South and Southeast Asia, ranging from Sri Lanka and the Indus basin to northern the Malay Peninsula and the Mekong.

The body is oblong and compressed. The greatest width of the head equals its post-orbital length. It reaches 15 cm in length.