Swordtails are members of the Poeciliidae family, and are found from Mexico, Belize, and Guatemala. These hardy and colorful fish make a wonderful addition to the passive community aquarium. Swordtails are easy to breed, and new color varieties are developed through selective breeding programs. The fry are born fully developed, and can be raised easily in a separate aquarium or net breeder inside the tank. The fish acquired the name from the long sword-like fin that protrudes from the male's tail. To reduce aggression, it is ideal to maintain a small school of 5 or more fish in the aquarium. Swordtails add interest and color to the passive community aquarium, and make a perfect addition for the novice to expert alike.