Xiphophorus hellerii

About This Species

Basic Description

A popular choice for beginners, the Swordtail is an active, brightly colored freshwater fish. From Central America, it is hardy and adapts well to a standard aquarium. As an omnivore, it enjoys a varied diet. Swordtails are social and best kept in groups, though males can be territorial. Energetic swimmers and known jumpers, they require a secure tank lid for safety.

Detailed Description

This species primarily occupies the tank's top and middle strata. Male territoriality is a key behavior, best managed with a high female-to-male ratio. As prolific livebearers, breeding is common and straightforward. Its preference for hard, alkaline water directly reflects its Central American riverine origins. The fish's active metabolism results in a moderate bioload, influencing filtration needs and maintenance schedules. A covered tank is essential to prevent jumping.

Scientific Description

Classed within Poeciliidae, *Xiphophorus hellerii* is a ray-finned fish (Actinopterygii) in the order Cyprinodontiformes. It is a livebearing toothcarp, a reproductive strategy that ensures high breeding success in captivity. Its natural ecology in low-flow Central American waters dictates its aquarium parameters for water movement and chemistry. The common name Green Swordtail references the wild phenotype and the male's characteristic 'sword'—an extension of the caudal fin.