The influence of increased stocking density on haemotology of Cyprinus carpio at various stocking densities was investigated. The groups were reared in the density of 5, 10, 15 and 20 individuals/ aquarium /cage. The aim of the study was to determine the response of Cyprinus carpio on red blood cells white blood cells, haemoglobin and haematocrit during increased stocking densities in cages and in aquaria. Results indicated that red blood corpuscles and haematocrit showed increase, where as white blood corpuscles showed decrease. However haemoglobin has not shown much variation. The response of carp to mild stress and the effect of increasing stocking on various blood parameters of fish is discussed in detail.