What is Gambusia affinis?
Gambusia affinis, appropriately named the "mosquito fish," is a small,
guppy-like fish ranging in size from approximately ¾ to 1 ½ inches
long. As its name implies, it is a natural predator of mosquito
larvae.

Larvae Consumption
Gambusia affinis is a voracious predator. According to statistics
cited in U.S. Navy research, a large female Gambusia is able to
consume 225 larvae within a one hour period, and a pair of half-grown
Gambusia are capable of consuming over 5000 larvae in 11 weeks. All
sizes of Gambusia feed on mosquito larvae; even fry only a few hours
old will attack young instars.

Reproduction Capabilities
Gambusia bear live young, producing an average of three to four broods
per summer at intervals of three to six weeks. The number of fry per
brood averages between 25 and 125. Reproduction usually occurs during
the warmer spring and summer months.

Cold-Tolerant Gambusia
More than 30 years of natural selection by Fattig Fish has resulted in
a genetically adapted cold-tolerant stock of Gambusia affinis able to
survive temperatures below -30° and to 100° Fahrenheit. This special
cold-tolerant strain is particularly well-suited to climates above the
39th parallel, where winter temperatures often prevent overwintering
of Southern Gambusia. Additionally, the cold-tolerant strain has been
observed to feed at 50° water temperatures, a distinct advantage over
other strains, which generally begin to feed at considerably higher
temperatures.