Swordtail
Xiphophorus hellerii · Fish, Vertebrate, Cold-blooded, Domesticated (aquarium variety)
Animal Family
Family Poeciliidae, Order Cyprinodontiformes, Class Actinopterygii
Animal Category
Freshwater Animal
Breed / Variety
Red-lined or Pineapple/Standard Green Swordtail with distinctive elongated caudal fin
Conservation Status
Least Concern on the IUCN Red List, with stable wild populations and widespread captive breeding.
About This Creature
A slender freshwater fish reaching lengths of 4 to 6 inches including the tail extension. Typically features a light greenish or translucent body with a distinct reddish-pink lateral stripe and a characteristic long, black-edged lower sword-like extension on the tail of males.
Physical Characteristics
Elongated compressed body, small terminal mouth, large eyes, transparent dorsal and pectoral fins, and a highly modified caudal fin in males featuring a sword-like lower lobe. Females lack the sword extension and are generally larger and rounder.
Behavior & Temperament
Active, peaceful, and social schooling fish that prefer living in groups. Diurnal activity pattern, excellent swimmers, sometimes prone to jumping, and males can occasionally show mild territorial displays toward each other.
Habitat & Diet
Origin Region
Central America, specifically from southern Mexico down to northwestern Honduras
Habitat
Freshwater rivers, streams, springs, and canals; Aquatic and free-swimming
Diet & Nutrition
Omnivore, feeding on algae, small insects, crustaceans, and plant matter in the wild; readily accepts flake food, pellets, and frozen foods in aquariums.
Lifespan & Health
Typically lives 3 to 5 years in captivity. Susceptible to common freshwater fish diseases like Ich, fin rot, and fungal infections. Livebearer reproduction with frequent fry production.
Special Characteristics
Famous for their sexual dimorphism, particularly the male's swordtail. They are also known for sex-reversing under certain genetic or environmental conditions, where some older females can transform into functional males.
Ecological Information
Occupies middle to upper water columns in freshwater ecosystems, serving as an important part of the food web by controlling mosquito larvae and small aquatic insects while serving as prey for larger predatory fish and birds.