killifish

noun

kil·​li·​fish ˈki-li-ˌfish How to pronounce killifish (audio)
1
: any of a family (Cyprinodontidae) of numerous small oviparous fishes much used as bait and in mosquito control
2
: any of various live-bearers (family Poeciliidae)

Examples of killifish in a Sentence

Recent Examples on the Web
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So far, Hector’s killifish has been found at over a dozen sites in Chiapas, a state of southern Mexico bordering Guatemala and the Pacific Ocean. Aspen Pflughoeft, Miami Herald, 8 Aug. 2025 Most species are holding fewer cards than the killifish. Brian Owens, Smithsonian Magazine, 26 Jan. 2024 Meanwhile, banded killifish, mumichog’s close cousins, live mostly in freshwater in the eastern United States — and are among the few vertebrate species known to be able to reproduce asexually. Gabe Allen, Discover Magazine, 19 Jan. 2023 See All Example Sentences for killifish

Word History

Etymology

killie killifish (perhaps from kill entry 3) + fish

First Known Use

1836, in the meaning defined at sense 1

Time Traveler
The first known use of killifish was in 1836

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Cite this Entry

“Killifish.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/killifish. Accessed 11 Sep. 2025.

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