Biometric features and reproductive biology of the dwarf chameleon fish Badis blosyrus from Brahmaputra River system of Assam, North-east India

The present study was carried out to understand the biometric features and reproductive traits of indigenous dwarf chameleon fish Badis blosyrus (Kullander and Britz, 2002). This species, a potential candidate for ornamental fish trade, holds significant conservation and commercial value but remains relatively understudied. Altogether seventy-five wild fish specimens were collected from the Brahmaputra River and its associated streams and wetlands of Assam during October 2021 to March, 2022. Morphometric and meristic characteristics were recorded. Important parameters estimated for reproductive biology includes sex ratio, gonad weight, gonadosomatic index (GSI), absolute and relative fecundity as well as egg diameter. Sexual dimorphism is well noticeable by their colour pattern, with adult males displaying bright colour and larger in size than the females. Gonadosomatic index (GSI) values ranged from 1.26 to 11.42 in male and 1.48 to 13.57 in females. The absolute fecundity varied from 892 to 940 eggs per fish while the relative fecundity ranged from 142 to 150 eggs per g of body weight. The fish due to its attractive and unique colour pattern have high demand in ornamental fish market. In view of limited knowledge on B. blosyrus, the present study aimed to generate baseline data which will be useful for conservation biology, designing breeding protocols and formulating sustainable management strategies. Keywords: Badis blosyrus, Biometric features, Fecundity, Reproductive biology, Ornamental value