• Scientific name: Xiphophorus montezumae
• Common name: Montezuma swordtail
• Group: Livebearers
• Habitat: Central America; Mexico
• Size: Males:4-6 cm (without the "sword") , female:6 cm
• Biotope: Rivers with thick vegetation.
• Social behavior: Peaceful, shy .
• Diet: Omnivorous
• Breeding: Easy
• Tank: Minimum 200 litres
• Population: 7-8 fish for 200 litres
• Decoration: Thick vegetation
• Temperature: 20-25 °C
• pH: 7-8
• Hardness: 10-20 NK°
• Lifespan: 3-5 years

Description: The Montezuma swordtail is one of the true wild swordtails originally introduced into the hobby. Today almost all of the swordtails available at local fish stores are many generations removed from wild fish such as this and have many different colors. The wild Montezuma most resembles what are sold today as green swordtails. However, the wild fish are larger, and in addition to the green body color they have a number of black spots — most evident on the male.

Swordtails in general make good community tank fish as long as it's a community of fish that does best in water conditions that are slightly alkaline and fairly hard (15 DH) with a pH up to 7.4 or so. In addition, they should have some salt in the water, perhaps a tablespoon to every 2 gallons or so. The tankmates in a setup like this would best be other livebearers such as other swordtails, platys, mollies and guppies. Most larger rainbow fish would also do well with Montezuma swords.

Montezuma swordtails are livebearers, which means that female gives birth to live babies fully capable of taking care of themselves. Females give birth about every 30 days or so, and they should have their own small tank of 2 to 5 gallons ikn which to drop their babies. Make sure to have artificial spawning mops or lots of floating plants in the tank for the babies to hide in. They tend to head toward the surface immediately after birth. Never put a female swordtail in one of those plastic “breeding traps” sold at your local fish store. It is much too small for her and will usually cause the female to either freak out and die or drop babies before they are fully mature.

If you are fortunate enough to find true wild Montezuma swordtails for sale, be sure and buy them. They are wonderful fish in their own right, but it's especially interesting to see where all of the various colors and types of swordtails available in the hobby came from originally.