swordtail

Table of Contents

Introduction References & Edit History Related Topics

Images

Swordtails (Xiphophorus helleri)

Body plans of Lampridiformes and Atheriniformes.

Read Next

Spider monkey swinging in a tree. (primate, jungle animal)

Why Do Animals Have Tails?

animal. Amphibian. Frog. Anura. Ranidae. Frog in grass.

Abundant Animals: The Most Numerous Organisms in the World

Sea horse or Seahorse, Hippocampus. Kingdom: Animalia Phylum: Chordata, Class: Actinopterygii, Order: Syngnathiformes, Family: Syngnathidae, Subfamily: Hippocampinae

9 Fish Named After Other Animals

Japanese spider crab

10 Animals With Evolutionary Traits Plucked Straight Out of a Nightmare

Malayan Leaf Frog - Megophrys nasuta

9 Animals That Look Like Leaves

Discover

Super Typhoon Noru over the western tropical Pacific Ocean as observed by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA Aqua satellite July 31 2017

What Is the Difference Between a Typhoon and a Super Typhoon?

Mayer Amschel Rothschild (1744-1855), founder of the house of Rothschild; lithograph by Friedrich Lieder, c. 1830.

Where Do Anti-Semitic Conspiracy Theories About the Rothschild Family Come From?

Santa Claus flying in his sleigh, christmas, reindeer

Was Santa Claus a Real Person?

Thumbnail for flags that look alike quiz Russia, Slovenia, Iceland, Norway

Flags That Look Alike

Close up of books. Stack of books, pile of books, literature, reading. Homepage 2010, arts and entertainment, history and society

12 Novels Considered the “Greatest Book Ever Written”

A Factory Interior, watercolor, pen and gray ink, graphite, and white goache on wove paper by unknown artist, c. 1871-91; in the Yale Center for British Art. Industrial Revolution England

Inventors and Inventions of the Industrial Revolution

A human Inuit skull in a stone chambered cairn in Ilulissat in Greenland. These ancient graves are pre christian and are at least 2000

14 Tough Questions Answered

swordtail

fish

Also known as: Xiphophorus helleri

Written and fact-checked by The Editors of Encyclopaedia Britannica

Article History

swordtail — swordtailSwordtail (Xiphophorus hellerii).

swordtail, (Xiphophorus hellerii), popular tropical fish of the live-bearer family Poeciliidae (order Atheriniformes). The swordtail is an elongated fish, growing to about 13 centimetres (5 inches) long and characterized, in the male, by a long, swordlike extension of the lower tail fin lobe. The fish is closely related to the platy and, like its relative, has been used extensively in genetic and medical research. Originally green with a red stripe on each side, the swordtail has been bred in many colour varieties.

This article was most recently revised and updated by John P. Rafferty.