Rohu

The rohu (Labeo rohita) is a large, fast-growing carp native to major river systems of the Indian subcontinent, including the Ganges, Brahmaputra, and Indus basins. It has an elongated, streamlined, silvery-grey body with a bluish sheen along the back and a distinctive small, pointed head with fringed lips adapted for feeding on plankton and plant material in midwater and at the surface. Rohu is one of the most economically important freshwater aquaculture species in South Asia, extensively farmed in polyculture systems alongside catla and mrigal carp. In the wild, it undertakes seasonal migrations for spawning and is an important component of river and floodplain fisheries across its native range.

• Elongated, cylindrical to slightly compressed body, silvery-grey with a bluish tinge along the back
• Small, pointed head relative to body size, with fringed (frilled) lower lip
• Single pair of small barbels, sometimes reduced or absent in adults
• Reddish tinge along the edges of paired and anal fins in some individuals
• Look-alikes: catla has a much larger, upturned mouth and deeper body; mrigal carp lacks the bluish back sheen and has a more slender profile

Rohu is native to the major river systems of the Indian subcontinent, including the Ganges-Brahmaputra basin across India, Bangladesh, Nepal, and Pakistan, as well as parts of Myanmar. It inhabits large rivers, floodplain lakes, and reservoirs, favoring open water in the middle depths rather than the bottom or surface exclusively. Rohu tolerates warm tropical to subtropical freshwater and benefits from seasonal flooding, which provides access to productive floodplain feeding grounds and triggers spawning migrations upstream. The species has been widely introduced beyond its native range for aquaculture purposes across South and Southeast Asia and parts of the Middle East and Africa.

Rohu is a column feeder, occupying the middle depths of the water body and feeding primarily on phytoplankton, zooplankton, and decaying plant material filtered or grazed using its fringed lips, complementing the surface-feeding catla and bottom-feeding mrigal in traditional polyculture systems. Adults undertake seasonal breeding migrations during the monsoon season, moving upstream into flowing river sections where females release large numbers of eggs that are fertilized externally and drift with the current before hatching; there is no parental care. Growth is rapid under favorable conditions, making rohu a preferred species for aquaculture ponds and tanks throughout South Asia. Wild populations have declined in some rivers due to damming, which blocks migratory spawning routes and habitat connectivity.