The seasonal condition (K) and relative condition (Kn) cycles and their changes with the growth of the fishChanda commersonii (Cuv. and Val.) for 2 yrs are presented. BetterK is shown by the smaller immature and first maturity stages and larger, almost senile groups but they show aKn factor below ‘1’. The actively breeding adults show a uniform fail inK but they give comparatively highKn values (above ‘1’). These changes inK andKn with the growth of the fish are clearly reflected in their seasonal cycles also.K cycle would thus appear to follow a pattern of build up and loss of body resources, indirectly following the breeding cycle while theKn cycle follow the breeding and feeding cycles directly, as shown by their seasonal changes and changes with growth of the fish for 2 yrs. Since only minor deviations from unity occur inKn factor it furnishes a more sensitive index of somatic difference between age groups, of breeding season and feeding cycle.