Ever increasing mosquito populations is a major cause for many human health hazards due to the transmission of the protozoan and microbial parasites. Additionally, usages of larvicides to control the mosquito population result in many health problems for human beings. Hence, it is suggested that bio-control of mosquito by controlling their larval populations through predator animals will be the best option. In the present study the common ornamental fish, black molly (Poecilia sphenops) is used in experiments designed to assess the predation of different instars of Anopheles mosquito larvae by this fish. Results indicate juveniles to adults of black molly predate on mosquito larvae. It is recorded that the molly actively chase the mosquito larvae and try to immobilize it by an active encounter with its jaws and then swallows early instars while the advanced instars are further attacked before consuming them. The early instars of mosquito larvae were active predators than the later stages. Present study shows variations with regards to the predation of different instars of mosquito larvae by black molly. The present experiment indicates that the black molly shows good efficacy towards mosquito larvae and hence this fish can be used effectively to control mosquito larvae of all the species.