Catla

The catla is a large freshwater carp native to rivers and floodplain wetlands of South Asia, prized as one of the three traditional 'Indian major carps' farmed alongside rohu and mrigal. It is distinguished by its broad head, large upturned mouth, and deep, laterally compressed body that give it a heavy, big-headed appearance compared to other carps. Catla are primarily surface and mid-water feeders, filtering plankton with specialized gill rakers, which lets them grow rapidly on natural pond productivity. They are among the fastest-growing and largest of the Indian carps, historically reported to exceed 1.5 meters in large river systems, though farmed fish are typically harvested well before reaching such sizes. Catla underpin much of South Asian carp polyculture and aquaculture economies.

• Large, deep, laterally compressed body with a distinctly broad, blunt head
• Wide, upturned mouth with a protruding lower jaw and no barbels
• Silvery-grey scales, darker on the back, often with a slight golden sheen
• Noticeable dorsal hump behind the head in larger individuals
• Large, coarse scales compared to the finer scales of rohu
• Distinguished from rohu by its broader head, upturned mouth, and lack of barbels; rohu has a more pointed snout and thin barbels
• Distinguished from mrigal by its deeper body and larger head

Catla are native to the river systems of the Indian subcontinent, including the Ganges, Brahmaputra, and Indus basins, as well as associated floodplain lakes and wetlands, and have been introduced widely across South and Southeast Asia for aquaculture. In the wild they inhabit large, slow to moderately flowing rivers and connected floodplain waters, moving into flooded areas during the monsoon to feed and spawn. In aquaculture, they are stocked in ponds, tanks, and reservoirs, where they occupy the upper water column and benefit from planktonic productivity. Catla tolerate a range of temperatures and moderate turbidity but favor warm, nutrient-rich water typical of South Asian lowland rivers and managed ponds.

Catla are primarily plankton feeders, using fine gill rakers to strain zooplankton and phytoplankton from the water column, mostly in the surface and mid-water layers, which reduces direct competition with the bottom-feeding mrigal and column-feeding rohu in polyculture systems. In the wild, catla undertake seasonal migrations, moving upstream or into flooded plains during the monsoon to spawn in fast-flowing water over open substrate, with eggs and larvae drifting downstream to nursery habitats. They grow quickly under favorable conditions, reaching sexual maturity within a few years. This combination of rapid growth, surface feeding, and prolific breeding has made catla central to South Asian carp polyculture, raised alongside rohu and mrigal to make efficient use of different pond niches.