It is found in fresh water and also known as mosquitofish or gambezi.
It is a viviparous organism as the fertilization and development take place inside the fish itself.
Importance of Gambusia:
Mosquito larvae are the prey of gambusia thus when they are put into ponds or drains they prey on these larva and decrease the production of mosquitos.
seedlings of these fishes are put into these ponds or drains which help to minimize the mosquito borne diseases such as dengue etc.