Everyone knows about mosquitos, but few Missouri residents have encountered mosquitofish. These little fish are known for mosquito control and thrive in brackish and vegetated waters, where many mosquitos hatch.
Mosquitofish females can grow to about 2.8 inches, while the males seldom grow larger than 1.2 inches long.
During the summer mating season, which usually lasts 10 to 15 weeks in Missouri, males actively search for female mating partners, which they court with nudging and fancy swimming demonstrations. Courtship rituals are often visible to observers as flashing in the water.
Mosquitofish are livebearers; they give birth to live young, instead of laying eggs. A few other livebearer fish you may be acquainted with are tropical mollies and guppies.
Each birth of live young is called a brood, and broods usually consist of between 10 and 100 young. A female can have several broods per season.
Mosquitofish prefer warm climates and only a few of the species survive Missouri's cold winters, but these few manage to sustain the population. More mosquitofish are showing up in central and north Missouri. Their spread is thought to be due to people stocking the fish for mosquito control. However, a few other native fish species also can control mosquitos and are better suited to Missouri's climate.