During the period 2014-18, a total of 219 cases of fish mortalities were being investigated under a passive surveillance programme. Among different disease incidences parasitic diseases were found to the major contributor accounting for 74.88% cases followed by bacterial diseases of 12.79%, mixed bacterial and parasitic diseases of 10.50% and viral diseases of 1.83%. Among different parasitic cases mixed parasitic infections (37.80%) were found to be premier cause of disease followed by argulosis (19.51%), dactylogyrosis (18.90%), myxosporeans (12.80%), trichodiniasis and ichthyophthiriasis (3.04%) and other parasites (4.88%). Among bacterial infections, aeromonads group account for 66.66% diseases besides few emerging pathogens of public health significance. Catla was found to be the most susceptible species and winter season being the most favorable season for occurrence of infectious diseases. Fishes weighing 100-500 g were most vulnerable to disease occurrence. This study generated a comprehensive disease incidence scenario in freshwater aquaculture in eastern India.