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Etymology/Derivation of Scientific Name
Maximum size: Known SL 78 mm (Miller et al., 2005).
Coloration: Males are mostly greenish, with the longitudinal stripes of reddish, blue or duller colors, and there may be rows of reddish spots in the dorsal fin. Females are similar in color, nut lack the sword and have a normally expanded anal fin. (Stevenson 1976). Quite variable, not normally showing pale iridescent-blue pigment between red striped on side (Rauchenberger 2005).
Counts: Dorsal fin rays 11-17, typically 12-14 (Minckley 1973).
External morphology: Lower caudal rays of male elongated into a "sword" (Hensley and Courtenay 1979) Males are easily recognized by the long sword-like process from the ventral lobe of the caudal fin (Stevenson 1976). Claw present at tip of gonopodial ray 5a (Rauchenberger 2005).
Distribution (Native and Introduced)
U.S. distribution: Established in Montana, Florida, Arizona, California and Nevada. (Hensley and Courtenay 1979) Hawaii and Canada (Dawes 1991; Jacobs 1969)
Abundance/Conservation status (Federal, State, NGO)
Macrohabitat: Diverse, including ponds, springs, shaded and sometimes very rocky arroyos, ditches, open lagoon and rivers with a variety of substrates; water clear to murky, muddy, or opaque, sometimes badly polluted; currents non to moderate; vegetation non to occasionally common; depth to 1.5m. (Miller et al., 2005).
Spawning season: Young 8.0-14 mm SL have been collected between 23 December and 28 March, suggesting a long reproductive season (Rauchenberger 2005). Possibly year round (Milton and Arthington 1983).
Spawning Behavior: Live bearing, all poeciliid males posses a gonopodium. After attaining sexual maturity, swordtails do not form mating pairs but are completely polygamous (Tamaru et al., 2001).
Fecundity: known to be as high as 242 fry/female (Breder and Rosen 1966), Spawns of X. helleri average about 30 fry/female (Tamaru et al., 2001).
Age at maturation: 10-12 weeks, or at 25-30mm TL (Milton and Arthington 1983; Dawes 1991).
Growth and Population Structure: Younger swordtails grow at a rate of just over .5 mm/day. The rate of growth slows after the fry attain sexual maturity. Accompanying growth is a dramatic alteration in morphology most notable in males with the extension of their caudal fin or "sword."
Food habits: Omnivorous (Dawes 1991). Terrestrial and aquatic insects are eaten along with phytoplankton and some macro algae (Arthington 1989).
Phylogeny and morphologically similar fishes
X. maculatus and X. variatus are often used for hybridization in the aquarium trade for obtaining ornamental species, because of their close relation. They are in the same subfamily as Poecilia latipinna and P. reiculata (Tamaru et al., 2001).
Protozoa (Trichondina), Monogenea (Dactlyogyrus and Gyrodactylidae) and Fungi (Saprolegnia) (Tamaru et al., 2001).
Commercial or Environmental Importance
X. helleri and the hybrids involving it are used in the aquarium trade worldwide (Tamaru et al., 2001).
This popular aquarium fish has been introduced in many places in Texas and elsewhere in the United States. Such transfers are to be strongly discouraged as they often have serious effects on native aquatic life (Miller et al., 2005).
Arthington, A.H. 1989. Diet of Gambusia affinis holbrooki, Xiphophorus helleri, X. maculatus and Poecilia reticulata (pisces: Poeciliidae) in streams of southeastern Queensland, Australia. Asian Fisheries Science, (2) 193-212.
Breder, C. M. and D. E. Rosen. 1966, Modes of reproduction in fishes. New York: American Museum of Natural History Press.
Dawes, J. A. 1991. Livebearing Fishes. A Guide to Their Aquarium Care, Biology and Classification. Blandforn, London, England. 240 pp.
Heckel, J. 1848. Eine neue gatting poecilien mit rochenartigen anklammerungs-organe. Sitzber. K. Akad. Wiss. Wien. Math. Nat. Cl. 1:289-303.
Hensley, D.A. and W.R. Courtenay, Jr. 1980. Xiphophorus hellerii (Heckel) Green swordtail pp. 554 in D.S. Lee et al. Atlas of North American Freshwater fishes. N.C. State Mus. Nat. Hist., Raliegh, i-r+854
Jacobs, K. 1969. Livebearing Aquarium Fishes. The Macmillan Company. New York.
Miller, R. R., W. L. Minckley and S. M. Norris. 2005. Freshwater Fishes of Mexico. The University of Chicago Press. Chicago, IL. pp 258-59
Milton, A. A. and A. H. Arthington. 1983. Reproductive Biology of Gambusia affinis holbrooki (Baird and Girard), Xiphophorus helleri, (Gunther) and X. malculatus (Heckel) (Pisces; Poeciliidae) in Queensland, Australia. Journal of Fishery Biology., (23): 23-41
Minckley, W. L. (1973). Fishes of Arizona. Phoenix, Arizona Game and Fish Department 293 pp.
Rauchenberger, M. 2005. Artificial Key to Mexican Poeciliidae. pp. 212-218 in Miller et al., 2005. Freshwater Fishes of Mexico. The University of Chicago Press. Chicago, IL.
Stevenson, H.M.1976. Vertebrates of Florida. University Presses of Florida, Gainesville pp.1-607.
Tamaru, C. S., B. Cole, R. Bailey, C. Brown and H. Ako. 2001. A Manual for Commercial Production of the Swordtail, Xiphpophorus helleri. CTSA Publication Number 128. December 2001.