Overview
The swordtail is one of the most popular starter fish in the hobby, and it is easy to see why. It is hardy, colorful, active, and full of personality. The wild fish is greenish with a red stripe, but breeders have created swordtails in bright reds, oranges, blacks, and mixed patterns. The standout feature is the long, pointed lower part of the male's tail fin, which looks just like a tiny sword.
Swordtails come from the streams and warm rivers of Central America, from Mexico down through Guatemala and Honduras. They are livebearers, which means the females give birth to fully formed, swimming babies instead of laying eggs. In a healthy tank they breed readily, so a group can grow quickly if the fry find hiding spots among the plants.
| Care level | Easy |
| Adult size | 5.5 in (14 cm) |
| Lifespan | 3-5 years |
| Temperament | Peaceful and active |
| Min. tank | 20 gal (75 L) |
| Temperature | 72-79 F (22-26 C) |
| pH | 7.0-8.2 |
| Diet | Flakes, pellets, veggies, and small live or frozen foods |
| Schooling | Small groups, more females than males |
The sword
Only the males grow the famous sword, an extended lower spike on the tail fin. They use it in courtship displays, flicking and showing it off to impress females and warn off rival males.
Living babies, not eggs
Swordtails are livebearers like guppies and mollies. A single female can give birth to dozens of tiny, ready-to-swim fry at once, and she can do it again every few weeks.
Where it lives
In the wild it swims in the flowing streams, rivers, and warm springs of Mexico and Central America, often in areas thick with plants where the current is gentle.
Keeping it happy
Swordtails are strong swimmers that like a longer tank with room to cruise and a secure lid, since they can jump. They enjoy some plants and appreciate slightly hard, alkaline water.
Good tankmates
Their peaceful nature makes them great community fish. Keep more females than males so no single female gets pestered, and pair them with other calm, similar-sized fish.
Fun facts
- Only male swordtails grow the sword-shaped tail extension.
- Females give birth to live, free-swimming young instead of laying eggs.
- Wild swordtails come from the streams of Mexico and Central America.
- They are strong jumpers, so a covered tank keeps them safe.
- Breeders have created dozens of color varieties from the plainer wild fish.
Frequently asked questions
Why do only some swordtails have a sword?
The sword is a male feature. Females have a normal rounded tail. The males use their sword during courtship displays to attract mates.
Are swordtails good for beginners?
Yes, they are one of the classic beginner fish. They are hardy, active, and forgiving, which makes them a great choice for a first community tank.
Will they have babies in my tank?
Very likely, if you keep males and females together. They breed easily, and the fry can hide among plants to survive. A group can grow fast.
How big a tank do they need?
Because they grow to several inches and love to swim, a 20 gallon or larger tank suits them best, especially a longer one that gives them room to cruise.
