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

Examples of killifish in a Sentence

Recent Examples on the Web In his own research, Whitehead has shown that Atlantic killifish, a small silvery fish found off eastern Canada and the United States, has adapted to live comfortably in estuaries plagued by heavy industrial pollution. Brian Owens, Smithsonian Magazine, 26 Jan. 2024 Most species are holding fewer cards than the killifish. Brian Owens, Smithsonian Magazine, 26 Jan. 2024 Some guppies live in havens that are largely predator-free except for the killifish, a small fish that only takes the smallest juvenile guppies. Ed Yong, Discover Magazine, 1 Feb. 2010 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 Below the iridescent slime covering much of the river’s surface, though, a greenish minnow-size baitfish called the mummichog—also known as the Atlantic killifish—was managing to eke out a living in the waters that abut the Elizabeth’s Superfund sites. Carrie Arnold, The Atlantic, 15 Mar. 2021 Both Hudson tomcod and New Bedford killifish, however, have unusual AHR molecules. Veronique Greenwood, Discover Magazine, 31 Oct. 2011 Take, for example, a population of Atlantic killifish (Fundulus heteroclitus). Avery Hurt, Discover Magazine, 26 Mar. 2021 This lucky population of killifish is probably an outlier, however. Avery Hurt, Discover Magazine, 26 Mar. 2021

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'killifish.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

Dictionary Entries Near killifish

Cite this Entry

“Killifish.” Dictionary, Merriam-Webster, Accessed 21 May. 2024.

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