新月鱼 xīn yuè yú

月光鱼【Xiphophorus maculatus】是热带鱼中一个重要品种，它和孔雀鱼一样小巧玲珑，五光十色，惹人喜爱。月光鱼体长鱼体长4~6厘米，它的适应性和繁殖能力都很强。它的特点是能与剑尾鱼类杂交，繁殖出新的品种。常见的月光鱼品种有：红月光鱼、蓝月光鱼、红鳍金月光鱼、金头月光鱼、双鳍月光鱼、帆鳍月光鱼、金头帆鳍月光鱼等。 

百度翻译提供：

The moonfish [Xiphophorus maculatus] is an important species of tropical fish. It is as small and colorful as the peacock fish, and is popular. The moon fish is 4~6 cm long. It has strong adaptability and reproduction ability. Its characteristic is that it can hybridize with swordfish and breed new species. Common species of moonfish are: red moonfish, blue moonfish, red fin golden moonfish, golden head moonfish, double fin moonfish, sail fin moonfish, golden head sail fin moonfish, etc.