Kallman's swordtail

Xiphophorus kallmani

Also known as Catemaco swordtail, Kallmani swordtail

FreshwaterFish

Care at a glance

Temperature: 73–82°F (23–28°C)
pH: 7.0–8.2
Adult size: 4.1 in (10.5 cm)
Minimum tank: 29 gal (110 L)
Temperament: Peaceful
Social behavior: Social
Swim level: Middle
Difficulty: Medium
Breeding: Easy
Rarity: Rare
Origin: Lake Catemaco, Veracruz, Mexico
Family: Poeciliidae

Overview

This is a large wild swordtail, so it needs real swimming length and is best kept as a group with several females per male to ease the males' constant courting. It works the middle water and covers ground, so a long tank matters more than a tall one. It is peaceful and mixes well with other robust, calm fish that handle hard, warm water, while smaller nervous species may find its size and activity too much. Feed generously and variously: flake, pellets, frozen and live foods, and vegetable matter such as spirulina and blanched greens. Plan on at least 110 liters, and more length is always better for an animal this size.

In the wild

Kallman's swordtail lives in Lake Catemaco, a warm volcanic lake in Veracruz, Mexico, with hard, slightly alkaline water that stays consistently warm. Reproduce that with a heated tank at 23 to 28 degrees Celsius and pH around 7.0 to 8.2, plenty of open water for swimming, and planted margins with some rock. Strong filtration and regular water changes keep pace with the waste a fish this size produces.

Good to know

Xiphophorus kallmani is a livebearing swordtail in the family Poeciliidae, described only in 2003 by Meyer and Schartl. At about 10.5 centimeters it is one of the largest wild swordtails, wild-type green, with the males carrying the long tail extension the genus is known for. Like its relatives it bears live young and breeds easily. It honors Klaus Kallman, a geneticist who spent much of his career on the heredity of Xiphophorus.

Did you know

Although Lake Catemaco is a long-studied crater lake, this big swordtail was not formally described until 2003, making it one of the more recently named fish in a very familiar aquarium genus.