“…Most of the species are considered to be endangered due to the declining of their natural habitat and also reduced in numbers and sizes of populations. The crucial factors responsible for the decline in the number and size of different sh population involve alternation of climate and habitat, pollution, dam construction, fragmentation, eutrophication, replacement of invasive or intentionally introduced species, over-shing, the aquarium pet trade, river ow modi cation, and even the consideration of the most optimistic climate change scenario points to the likelihood of ex-situ management of many species for their survival (Jeong et al 2012;Kelly et al 2013;Reis 2013;Gupta and Homechudhuri 2015;Gallardo et al 2016, Pauly andZeller 2016;Medeiros et al, 2016;Gold et al, 2017;Santos et al, 2017;Filho et al 2018;Martinz et al 2018;Mahboob et al 2019;Lopera-Barrero et al 2019).…”