Genus name: Xiphophorus Helleri
Distribution: Southern Mexico,
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
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
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.
For more information on
Swordtails and other livebearers: