Age structure of a population represents the ratio of the various age classes in a population to each other at a given time. Age structure is a function of growth and death. Study was undertaken the period November 2015 to October 2016 from the tributary of the Ganga river (Ghaghra river). The total length of fishes varied from 15.7 to 88.7 cm in 0+ to 8+ age classes. The age structure of C. mrigala indicated that the 2+ age group was dominated in the exploited stock from the Ghaghra river at Faizabad. The age classes 0+ and 1+ shared 9.03% and 16.51%, respectively. The bell shaped age pyramid was recorded.