Marine copepods are considered as an ecologically and economically important organism in assessing the fish stock since it is serving as prime feed for most of the brackish water and marine fishes. Hence, the present attempt was made to recognize the feeding and fecundity behavior of Oithona rigida using four different microalgal diets viz: Chlorella marina, Coscinodiscus centralis, Chaetoceros affinis and Skeletonema costatum. The feeding rate of the marine copepod, O. rigida increased with increasing body size. Similarly, the feeding rate also proportionately increased with algal food concentration.Oithona rigida prefers to feed more on C. marina (98.53%) than other algal prey such as C. centralis, C. affinis and S.costatum. O. rigida has exhibited maximum survival in the highest algal concentration when fed with 50:50 combination of C. marina:C. centralis . The highest egg production and hatching success were seen in the larger sized copepod (0.84 mm) at an optimum temperature (26±2oC) and higher algal food concentration (15,500 cells/ml). The study indicated that combination of C.marina and C.centralis with maximum (12.5 μg/l) algal concentration might be a suitable algal food source for effective cultivation of O. rigida. Besides, it is clearly proved that O. rigida have high reproductive capacity and therefore can be considered as most suitable candidate species for mass culture of live feed for the commercial seed production of finfish and shellfishes.

copepod, Oithona rigida, feeding rate, survival rate, fecundity.