Hematology profile of M. In monitoring the health status of this prawn species, which is a potential animal for fresh water aquaculture, dayanum would be useful as well as a good model for monitoring the level of contamination of fresh water habitats. Freshwater prawn haemocytes, Macrobrachium dayanum, were categorised into seven groups based on morphology and behaviour, such as the development of pseudopodia, the encapsulation of foreign clumping particles, etc., under a phase contrast microscope and their reactions with different stains. Prohaemocytes, plasmatocytes, spindle cells, granular haemocytes, spherule cells, adipohaemocytes and cystocytes were among the seven types of haemocytes. Structural information and their importance in the classification of haemocytes along with probable functions such as food transport, phagocytosis and foreign particle encapsulation, protection against different infections, hardening of exoskeletons, prevention of blood loss by encouraging immediate clotting, containment of invasive species and detoxification have been addressed.