Any of several small freshwater live-bearing fishes of the genus Xiphophorus of southern North America, especially X. maculatus and X. variatus, popular in aquariums for their bright and variable colors.

• 剑尾鱼一种北美洲南部产剑尾鱼属小型淡水胎生鱼，尤指新月鱼属和杂色新月鱼，因其鲜明而多变的颜色而常养于水族馆中