Background and Objectives:In recent years, resurgence of mosquito-borne diseases has become a serious health problem in India. In the present study, Stigmatogobius sadanundio, a common indigenous fish, has been tested for its biocontrol potentiality for controlling Culex quinquefasciatus larvae. This small larvivorous fish can consume large number of Culex larvae even in the presence of alternate prey. This is the first report on the mosquito control ability of this fish.Materials and Methods:Experimental fishes were captured from tidal canals of Rupnarayan River in Purba Medinipur district, West Bengal. Mosquito larvae, pupae, and chironomid larvae were collected from Tamralipta municipality drainage system. Predation efficacy of the fish was evaluated on C. quinquefasciatus larvae and pupae as well as on Chironomus ramosus larvae which were collected from the drainage system of Tamralipta municipality and reared in the laboratory maintaining similar water parameters. Prey were offered to the fish separately and in paired combination to study its dietary preference.Results:S. sadanundio is a diurnal predator consuming significantly large number of prey during daytime. It prefers mosquito and chironomid larvae over mosquito pupae. The rate of predation was very high during 1st h of predation. It consumed more chironomid larvae in the presence of mosquito larvae during daytime but consumed large number of mosquito larvae as compared to other larvivorous fish.Conclusion:S. sadanundio, an indigenous fish, is an effective biocontrol agent for the larvae of C. quinquefasciatus in laboratory condition. Even though the presence of alternate prey chironomid larvae influences the predation rate, it consumed large number of mosquito larvae. However, careful controlled field trials must be conducted before this fish is used as a biocontrol agent.