author(s)
Sarmin Akther, Maksuda Akhter and Mosharrof Hossain

abstract
The present study deals with length-weight relationship of two Gangetic Mystus, Mystus tengra (Hamilton, 1822) and Mystus cavasius (Hamilton, 1822) collected from local fish market of Rajshahi City Corporation from September 2010 to February 2011. Considering the size of frequency, the total length ranged from 65mm to 97mm in M. tengra and 102 mm to 148 mm in M. cavasius. The total mean weight ranged from 2.2g to 7.4g in M. tengra and 10.6g to 20.2g in M. cavasius. The condition factor (K_o) was 0.873±0.036 and 0.678±0.067 in M. tengra and M. cavasius respectively. However, the calculated relative condition factor (K_n) was 0.972±0.045 and 1.030±0.107 were in M. tengra and M. cavasius respectively.