The Mosquitofish is a small, light-colored fish with semi-transparent fins. Females usually have a black stripe near their eye area, and light spots can be seen on the caudal and dorsal fins of both sexes. Due to its size, shape and reproductive habits, it can easily be mistaken for a guppy. Males typically reach 1.5 inches and females 2.5 inches. These fish are live bearers and pregnant females are easily spotted by their gravid spot, the darker area on their bellies where they hold their fry.
Mosquitofish are opportunistic carnivores that feed on a range of terrestrial insects from ants and flies to aquatic invertebrates like bugs, beetles, fly larvae, zooplankton, filamentous algae and fragments of fruit and other plant tissues. If needed, Mosquitofish change their diet to other food sources to survive.
Mosquitofish can tolerate water temperatures between 33°F and 104° F, but like temperatures around 80° F and water with a pH between 6.5 and 8.0. Juvenile Mosquitofish are more thermally tolerant than adults, allowing them to colonize and exploit warm patches of the environment with increasing growth, survival, and maturation rate.
 If you are stocking your pond with Bass, Catfish or Bluegill, Mosquitofish are a wonderful simultaneous addition for adding forage - as well as insect control - to your pond. They are the first link in the food chain.