In nature, freshwater prawn migrates from river to brackishwater for breeding and the juveniles return back to the river system for growth and development. Prawn move upstream, entering lakes and even paddy fields. Migration of the prawns is induced according to the physiological conditions which are mainly controlled by light intensity and water current. Though biology and physiology of prawns have been discussed at large, no effort has been made so far to study those characteristic behaviors of prawns. Findings of this investigation may help in formulating new strategies while planning and designing water control structures or barrages across the fresh water rivers in estuarine/coastal areas so as to minimize their adverse impact on prawn migration to upstream river side which is essential for completion of prawn life cycle. This study may be also useful in evolving a new system for efficient collection of the prawn brooders/ berried female from the natural resources as well asculture ponds. Apart from being a fundamental research, this investigation has applied values in further development of prawn aquaculture.