Xiphophorus hellerii Heckel, 1848
Green swordtail
photo by Ramani Shirantha

Family:  Poeciliidae (Poeciliids), subfamily: Poeciliinae
Max. size:  14 cm TL (male/unsexed); 16 cm TL (female)
Environment:  benthopelagic; freshwater; brackish; pH range: 7 - 8; dH range: 9 - 19, non-migratory
Distribution:  North and Central America: Rio Nantla, Veracruz in Mexico to northwestern Honduras. Africa: Feral populations reported from Natal and eastern Transvaal as well as in Lake Otjikoto, Namibia (Ref. 7248). Several countries report adverse ecological impact after introduction.
Diagnosis:  Dorsal spines (total): 0-0; Dorsal soft rays (total): 11-14; Anal spines: 0-0; Anal soft rays: 8-10. This species is distinguished by having a medium to large swordtail with a long straight caudal appendage; midlateral stripe may be dusky or brownish (northern populations) or red; 2 additional reddish stripes may be present above midlateral line and one beneath; terminal segment of gonopodial ray 3 produced into a crescent-shaped hook and blade pointed distally; ray 4a curves strongly backward over the blade at an angle greater than 90°; distal serrae of ray 4p reduced in size and number and proximal serrae rather slender; terminal segment of ray 5a produced into a claw, several times larger than the distal serrae of ray 4p (Ref. 52914). Description: Body elongated; head pointed. There are many color forms due to the very extensive natural habitats. For green swordtail, the ground color is olive gray; scale rows along the middle of the body are green to blue; belly is white and there is a light red, dark red or brown longitudinal line on the flanks in all populations (regional forms). In a few variants, there can be one or two additional lines above and one or two below this line. In almost all populations, the dorsal fin has spots or flecks of red. This coloration can also appear in the caudal fin. The sword of males is bright yellow and edged more broadly in black below than above. Old fish (3 to 4 years old) can have a totally black sword from the caudal fin all the way to the tip of the sword.
Biology:  Adults are found mainly in rapidly flowing streams and rivers, preferring heavily vegetated habitats (Ref. 26130). They occur in warm springs and their effluents, weedy canals and ponds (Ref. 5723). They feed on worms, crustaceans, insects and plant matter (Ref. 7020). Used for genetics research (Ref. 4537). Especially the red varieties are very popular aquarium fishes (Ref. 1672). Aquarium keeping: the males aggressive towards each other; minimum aquarium size 80 cm (Ref. 51539).
IUCN Red List Status: Least Concern (LC); Date assessed: 29 March 2018 Ref. (130435)
Threat to humans:  potential pest
Country info:   
 


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