Background and objectives: Ever increasing population and lack of adequate health care facilities, particularly for the rural masses are a matter of concern for India. The major concern of India is the spread of vector borne diseases by mosquitoes. Mosquitoes are vectors of different pathogenic organism like protozoan, nematodes and viruses. They spread diseases like malaria, filaria, chikungunya, dengue and yellow fever etc. Culex transmits filariasis, Japanese encephalitis, Chikungunia, Ganjam and other Encephalitis diseases in the World. Puntius conchonius fish was used as a biocontrol agent against larvae of Culex. The predation potential of P. conchonius against Culex larvae was analyzed in the presence and absence of Hydrilla plant. Methods: The present experiment was designed and carried out in the laboratory of Biological Sciences, MGCGV, Chitrakoot, Satna (MP) . Fourth instars larvae of Culex were collected from stagnant water of natural pits, nearby university grounds (campus) and was reared in plastic cane (15-liter capacity) with unchlorinated tap water in the laboratory and was maintained at room temperature 28+ 20C & pH 6.5. P. conchonius fish were collected from Payaswani (Mandakini) river and reared in the aquaria with tap water at same temperature and pH. Results: The fish presented a high predation rate both in presence and in absence of aquatic weeds. Average feeding rate was 292.2 larvae / fish/day in the absence of aquatic weeds and 288.3 larvae/ fish/day in the presence of aquatic weeds in similar physico - chemical condition in the laboratory. Interpretation and Conclusion: The maximum feeding of the fish was 587 larvae / fish in the absence of weed where as minimum were 28 larvae/ fish with Hydrilla. The result was statistically analyzed by student‘t’ test. The value of t is 7.674 which is significant at P=<0.01 level.