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Livebearers / Poeciliidae / Swordtail

Swordtail
Xiphophorus helleri

Synonyms: Mollienisia helleri, Xiphophorus brevis, X. jalapae, X. rachovii, X. strigatus
Physical description: The Swordtail is an elongated species with a slender body. Males possess a characteristic, sword-like appendage formed by the lower rays of the caudal fin. The original form imported to the hobby has an olive green back with greenish-yellow flanks. A reddish stripe, bordered by greenish areas, extends from the the snout to the caudal fin.The fins are greenish, while the sword is variable. Most Swordtails available today differ in coloration do to years of selective breeding.
Size/Length: Males to 4" (10 cm), females to 4.7" (12 cm)
Similar species: Other Xiphophorus species
Habitat: Occurs in a wide range of habitats in Central America; Mexico, Guatemala, Belize, and Honduras.
S: all
Aquarium: A tank measuring 20" (50 cm) with a capacity of 10 gallons (38 L) is only suitable for young fish under 2.8" (7 cm) in length. If adult fish are kept in a tank this size, aggressive tensions may be present. A 28" (71 cm) tank with a volume from 20-25 gallons (76-95 L) is more suitable. Leave open swimming areas and use planting along the back and edges of the tank. A cover of floating plants can be used to provide refuge for fry.
Water chemistry: pH 7.0-8.3 (7.3), 10-30 dH (15), 68-82°F (20-28°C)
Social behavior: A fish recommended for a community tank having fish that can tolerate neutral to alkaline water conditions. Older individuals, especially males, will become combative in cramped conditions. It is best to keep one male with two or three females.
Suggested companions: Colisa , Trichogaster , other Xiphophorus , Corydoras , loricarids, tetras tolerant of hard water
FOOD: Flake; small pellets; live; worms, crustaceans, insects, insect larvae.
SEX: Males are smaller, possess a gonopodium, and have a sword-like appendage on the caudal fin.
Breeding techniques: After a gestation period of four to six weeks, the mother gives birth to 50-120 young. Suggest separating the pregnant female from other fish. The fry are eagerly consumed by the parents and other fish. The fry measure about 0.3" (8 mm) when they are born, and grow quickly.
Breeding potential: 3. An easily bred fish, although the young are hard to protect unless a breeding trap or other means of refuge is used.
Remarks: Many different color morphs are available including red, green, red-eyed, albino, neon, Lyre-tail, Wag tail, Simpson, and the Tuxedo. Besides these many cultivated forms, there are a number of separate wild populations with varying colors and patterns. Swordtails are known for undergoing "sex-reversals," when females appear to become males. This occurs most commonly to to five months after birth and in old females. When this change occurs early in life, a male is simply going through late development. Sometimes old females develop male characteristics after they are no longer fertile.
Difficulty of care: 1. Swordtails are fish that are suitable for a beginner's community tank.


By Rhett Butler   Mongabay.com