Neolissochilus hexagonolepis (common name: copper mahseer or chocolate mahseer[1]) is a species of cyprinid in the genus Neolissochilus.[2] It inhabits India, Bangladesh, Nepal, Myanmar, Thailand, Malaysia, Indonesia, China, Bhutan, Pakistan and Vietnam. It has a maximum length of 120cm (50inches) and a maximum published weight of 11kg (24lb).
In 2021, the Indian state of Sikkim declared Copper Mahseer, locally called 'Katley' as the State fish.[3]
The fish is found in different altitudes of the state of Sikkim, mainly in the Teesta and Rangit rivers and their tributaries.[3]
In 1992, ICAR-National Bureau of Fish Genetic Resources, Lucknow categorized the fish as an endangered specie. In 2014, IUCN, categorized it as an endangered specie.[3]