Home › Words › M › mosquitofishmosquitofishmosquitofish · noun — any of several small fish that feed on mosquitoes, but especially those of the genus Gambusia.Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom mosquito + fish.nounAny of several small fish that feed on mosquitoes, but especially those of the genus Gambusia.Definitions & examples from Wiktionary (CC BY-SA 3.0).