Neolissochilus hexagonolepis

Neolissochilus hexagonolepis (common name: copper mahseer or chocolate mahseer ) is a species of cyprinid in the genus Neolissochilus. It inhabits India, Bangladesh, Nepal, Myanmar, Thailand, Malaysia, Indonesia, China, Bhutan, Pakistan and Vietnam. It has a maximum length of 120.0 cm and a maximum published weight of 11.0 kg.

In 2021, the Indian state of Sikkim declared Copper Mahseer, locally called 'Katley' as the State fish.

Distribution
The fish is found in different altitudes of the state of Sikkim, mainly in the Teesta and Rangit rivers and their tributaries.

Endangered Status
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.