This original piece of work highlights the results of studies carried out on the survey of ecto- and endo- parasitic helminths of some freshwater fishes of Bhopal, India in relation to the physico-chemical parameters of water, identification and classification of parasites, histo-pathology of the organs infected by them, their effect on the haematological parameters, gonado-somatic index, fecundity and histology of ovaries. Helminth parasites damage the organs of fishes on which they subsist. They interfere with the physiological activities of affected fishes and retard their growth which causes economical loss to the fishery industry. Beside this, there is always a possibility of their transfer to human beings. It is, therefore, this work assumes importance.