Definition of swordtail in US English:



  • A livebearing freshwater fish of Central America, popular in aquariums. The lower edge of the tail is elongated and brightly marked in the male.

    Xiphophorus helleri, family Poeciliidae

    • ‘Such video techniques have been particularly effective in female mate choice studies in fishes, including guppies, sticklebacks, and swordtails.’
    • ‘Many fish lay eggs, but some - including common aquarium fish such as guppies, swordtails, and mollies - retain the eggs inside their bodies until hatching.’
    • ‘For example, in swordtails, male - male competition and female choice both contribute to the greater reproductive success of larger males.’
    • ‘If true, he said, the evolution of this mating preference might help explain the evolution of swords in male swordtail fishes.’
    • ‘One extreme, yet very thoroughly analyzed situation, is found in the swordtails and platyfish of the genus Xiphophorus.’
    • ‘Comparative approaches for examining processes of sexual selection have been applied to a variety of systems including spiders, mites, swordtail fish, guppies, frogs, manakins, and house finches.’
    • ‘Here, we examine male species recognition via odor cues in the swordtail fish.’
    • ‘Of course, I don't have room for 20 or so swordtails in my tanks, so I'm going to have to find a home for some of them…’
    • ‘Male swordtails in the genus Xiphophorus display a conspicuous ventral elongation of the caudal fin, the sword, which arose through sexual selection due to female preference.’
    • ‘An examination of correlations between parameters of growth in multiple species of swordtails points to several possible targets of selection.’
    • ‘Poeciliids, namely guppies and swordtails, are favorite subjects of sexual selection studies, in particular those concerning mate choice and its role in the maintenance of male secondary sex traits.’