Swordtail fish (Xiphophorous hellerii) are a very popular community aquarium fish. Their popularity stems from their ease of care and peaceful nature. They have quite unique types of fins with a great variety of colors, making them commonly referred to as Red swordtails or Green swordtails. Today, they are bred to achieve various colors and, as a result, great deals of different types exist.
In the wild, swordtails usually have olive green bodies with a red stripe that stretches along the body. Their natural habitat is in Central America and North America, where they were discovered in 1848. Swordtail fish are average size freshwater species; males are typically slightly smaller than females (6.3 inches) and they reach 5.5 inches maximum. They live in groups but are not a schooling fish. One of the things that make them so popular is their hardiness, as they can survive in very diverse environments.