Genus name: Xiphophorus Helleri
Distribution: Southern Mexico, Guatemala
Length: males up to 4″ (10cm) excluding sword, females up to 4.7″ (12cm)
Minimum Tank Length: 24″ (60cm)
Water Temperature: 70-79F (21-26C)
Diet: Worms, crustaceans, insects, dried food, plant matter
Water: medium-hard and slightly alkaline
The Swordtail is a slender, laterally compressed fish, which is so-called because the male has a long ‘sword’ at the bottom of his tail. The female Swordtail does not have this.
The Swordtail is generally compatible with other fish, but may be aggressive to smaller fish, particularly if in a small aquarium, so care must be taken when deciding on their companions.
Like the Platy, the Swordtail has been bred in captivity for many years, and as a result there are many colour forms available, but the most popular is the red variety. There are even some Swordtails with ‘lyre-shaped’ tails, or even tails with an upper and lower sword.
As with many other livebearers, the male and female Swordtail are easy to distinguish. Apart from the sword, the male has a gonopodium (modified anal fin), whilst the female is larger.
Like most livebearers, Swordtails are very easy to breed, and for that reason are ideal for beginners. Keeping at least 2-3 females for each male will help ensure the female Swordtails aren’t harassed too much.
When breeding, the female Swordtail will give birth to anywhere from 20 to 100 live young, after a gestation period of four to six weeks. These young Swordtails are free swimming from the outset, and will grow rapidly.
To ensure the best survival rate, it is best to remove the female Swordtail from the main aquarium and move her to a nursery aquarium before she gives birth. A few young Swordtails may survive in a community tank if there are sufficient plants for them to hide in, but generally most of them will get eaten, either by their parents or the other occupants of the aquarium.