Swordtail
Swordtail, a freshwater tropical fish, distinguished by a long tail spike on the male. The swordtail is one of the most popular fish for home aquariums. It is native to Central America. The original stock is iridescent green with a red stripe on the sides. However, many varieties, differing greatly in color, have been bred. The color variations include red or golden, both with black markings. Swordtails grow up to about 2 ½ inches (6.4 cm) long, not including the spike. They are live-bearers; that is, the female gives birth to live young.
The swordtail is Xiphophorus helleri of the family Poeciliidae.