Koi Swordtail
Xiphophorus helleri
By John Moyles
The swordtail is a species of fish in the family Poeciliidae of order Cyprinodontoforms. It is a livebearer, like its close relative the platy (X. maculatus) and it can cross breed with it. It is native to North and South America with a range from Southern Mexico to Honduras.
Males are slender and have a long sword shaped caudal fin extension formed by the lowermost eight fin rays. Females are stockier in build. Showa Koi Swords are white and red in color and typically have red eyes.
They are omnivorous in the wild and feed on insects, detritus, algae and plants. Flakes and pellets should make up the bulk of their diet and should be supplemented with live, frozen and freeze dried foods.
Swordtails are a livebearing toothcarp that belong to the family Poecilliidae. It shares this family with its close cousins; mollies, guppies and swordtails. Males can be identified by their tubular “gonopodium” which is a modified anterior portion of the anal fin. Females have a triangular shaped anal fin. Place two or three females with a male and breeding should take place almost immediately. Females give live birth 24 to 30 days later and should be separated into a “breeder box” when she is close to her due date. Babies are born fully formed and need no additional care other than very small foods such as powdered flake foods. Females can store sperm for several months.
Platies are a very peaceful fish and make great tankmates for similar sized “community” fish. Keep more females than males to reduce pestering.