Xiphophorus hellerii Heckel, 1848

Size

Description Male green swordtails grow to a maximum overall length of 14 centimetres (5.5 in), while females reach 16 centimetres (6.3 in).

Etymology

The name "swordtail" comes from the elongated lower lobe of the male's caudal (tail) fin.

Sexual Dimorphism

This species has moderate sexual dimorphism: females are larger than males and lack the characteristic "sword".

Wild Coloration

The wild form is olive green, with a red or brown lateral stripe and speckles on the dorsal fin, and sometimes on the caudal fin too. The male's "sword" is yellow, with a black edge along its lower margin.

Captive Color Varieties

Captive breeding has produced many color varieties, including black, red, and many combinations of these patterns, for the aquarium hobby. All varieties share the dark-red or brown central stripe.

Habitat

The green swordtail prefers swift-flowing, heavily vegetated rivers and streams, but is also found in warm springs and canals.

Diet

It is omnivorous, and its diet includes both plants and small crustaceans, insects, and annelid worms.