Species/genus: Xiphophorus helleri

Origin: Mexico

Temp: 72-80°F (22-26°C)

pH: 7 to 7.5 dH: Medium To Hard

Temperament: Peaceful, males sometimes fight

Adult Size: 3-5in (7-13cm)

Minimum Tank Size: 10 gallon

Feeding: Eats everything

Breeding: Livebearer, young must be protected from parents in most cases

Comments: A popular beauty, comes in many variaties and colors. Will jump from uncovered tanks.
Comment by TreasuresSecret:

Swordtails are friendly fish, and can live with almost any other nonagressive or low agression fish, or snail. They will become agressive when their tank space has been threatened, as when overcrowding occurs. They will also behave in an apparently agressive manner when mating. the male will chase the female(s) around the tank, attempting to “stab” them with the fin protrusion he is so named for. If there are numerous swordtails, remember that at least three males is a good idea. If you only have two males in the tank, one of them may become stressed, usually the submissive male. Therefore, it is a good idea to remove him from te tank. Of those that remain, keep one or more than three in the tank. Remember that with Swords (this applies to Mollies as well), they prefer community. In other words, more than one friend. For food: tropical fish food works wonders, and I supplement their diet with tubafex worms, which they and all other animals in the tank absolutely adore. S! tick to fish flakes for feeding regularly. Uneaten tubafex worms will litter the auarium floor and create unwanted waste. To feed, use about i/3 of a cube. I recommend Wardley’s.
The tank temperature is not hard to keep, and it is around where most livebeareres prefer it to be: 72-82 degrees F. Swords bear live young, and to protect these young, you will want to make sure you have fry grass, or some sort of plant with sharp ends so that the little guys can hide. As unpleasant as it sounds, some adults will “dispose” of the young with haste. Fry grow up very quickly, reaching breeding age after only three months following birth. To determine if yours is male or female, simply look for the swordtail’s distinguishing trait. Males have a long, pointed (sometimes striped) protrusion on the bottom of the tailfin that does actually resemble a sword! ( in other livebearers, the fin on the stomach is rounded in females and pointed in males).
For more information from moderators and other fish fans out there, I suggest checking out the message board and posting any other questions you may have. They will be answered with haste!