Species Spotlight: Freshwater Swordtails

Freshwater swordtails are a freshwater livebearer species from Northern and Central America. Swordtail fish come from clean flowing waters and prefer a planted aquarium of 30 gallons and larger with a clear section for free swimming and a little current. They like warm water but can survive down to more temperate temperatures. Being omnivores, they prefer a mixed and varied diet of soft algaes (spirulina, etc.) and proteins (bloodworms, daphnia, grindal worms, brine shrimps, etc.). This species has been captive bred for generations and comes in a wide assortment of colors and finnage shapes. Males typically display a rather pronounced sword on their tailfins. Some wild swordtail species have tails in excess of 7″ or longer. The feeding of live foods is said to enhance the development and growth of the male’s swordfin.

Females are larger and more rounded with some displaying a gravid patch once they’ve reached sexing age at six to eight weeks old. Males also develop a gonipodium fin at this age and the two sexes should be separated once they can be identified as males and females. Once sexually mature, females can be impregnated by males so keep the sexes separate unless you intend to breed them. Pregnant females will drop anywhere from 5-30 fry approximately every thirty to forty days.