Swordtail
(Xiphophorus Hellerii)
Alternate Names:
Swordie
Lyretail

Geographic History

These interesting little fish range from Veracruz, Mexico all the way to northwestern Honduras.

Enviornment

Swordtails love open water swimming so keep plenty of space in the middle of your fish tank. Provide tall plants along the sides and rear of your aquarium for cover.

These little guys are excellent jumpers and you will need to have a tight fitting hood on your aquarium. Fish make terrible paratroopers.

Compatibility

The males may show aggression to other male Swordtails and fish of the same size when there are to few females in the aquarium. Keeping three to four females for each male reduces the chance of aggression.

These little guys get along great with other species of Livebearers. Large Cichlids should not be kept with them though. They make a great meal for fish like Jack Dempsey and Oscar.

If you keep them with Platys, they may spawn and create hybrid fish.

Sexing

Males have a "sword" protrusion on the bottom of their tail fin. Females have fan shaped anal fins. The anal fin on males is very narrow and rod like. It is used during spawning to impregnate the females. Males may grow longer than females when adults.

Behavior

These little fish spend a fair amount of time grazing on algae and nibbling plants. They don't shoal, but they are less aggressive and happier in large numbers of their own kind. These are active swimmers and they are constantly on the go.

Be sure that you have several females for each male. After the males establish an order of dominance, the lead male will chase the females relentlessly. Without many females to spread this behavior around, all your females will be stressed to death with constant spawning behavior.

Breeding

Swordtails will breed in a community aquarium if there are plenty of tall plants for cover. The females carry the eggs inside their bodies and give birth to live, swimming fry. They will also spawn with Platys and create hybrid fish.

If your aquarium has many fine leafed plants, the fry will hide among them and many will survive. The parents and other fish will eat the fry, but you may need the crowd control. The females give birth to a couple hundred fry at a time and can continue to do so every one to two months.

If you have a dedicated breeding tank, you should remove the adults after spawning occurs. They will actively seek out and eat the fry.

Fry are born free swimming and will feed on crushed flake and baby brine shrimp. Keep excellent water quality by doing 10% daily water changes, being careful not to suck the fry out with the old water. Be prepared for dozens of juveniles if you breed these fish outside of a community tank.

For more information, go to Wikipedia's Swordtail page.