Montana Field Guide

Help

Montana Field Guides

Home - Other Field Guides
- Kingdom - Animals - Animalia
  - Phylum - Vertebrates - Craniata
    - Class - Fish - Actinopterygii
      - Order - Killfish / Mollies - Cyprinodontiformes
        
        Family - Livebearers (Mosquitofish / Mollies / Swordtails) - Poeciliidae
        
        Species - Green Swordtail - Xiphophorus hellerii

Green Swordtail - Xiphophorus hellerii

Image Copyright and Usage Information

Non-native Species

Global Rank: G5
State Rank: SNA

Agency Status
USFWS:
USFS:
BLM:

General Description

This tropical aquarium fish is an illegally released pet fish. The native range is southeastern United States, Mexico, and Central America.

Diagnostic Characteristics

Most are solid reddish orange; some are reddish orange with black fins or reddish orange with black mottling. Swordlike tail fin usually has black edges. The classical green variety with red and yellow stripes on sides is rare in Montana waters.

Observations in Montana Natural Heritage Program Database

Number of Observations: 7

(Click on the following maps and charts to see full sized version) Map Help and Descriptions

Relative Density

Recency

(Observations spanning multiple months or years are excluded from time charts)

Habitat

Can exist in Montana only in warm springs, ponds, and resultant streams in water temperatures of 68-80 degrees F.

Food Habits

An avid feeder, utilizing any organisms or organic debris which are suspended in the water. Includes both zoo- and phytoplankton as well as small instars of aquatic insects.

Reproductive Characteristics

Sexually mature in 3-4 months. Internal fertilization. Several broods per year under favorable conditions.

Management

The management of this and other native and non-native fish species and their habitats is outlined in Montana Fish, Wildlife and Parks' 2023-2026 Statewide Fisheries Management Plan

Useful Links:
Central and Eastern Montana Invasive Species Team
Montana Invasive Species website
Aquatic Invasive Species

Stewardship Responsibility

References

Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- Joslin, Gayle, and Heidi B. Youmans. 1999. Effects of recreation on Rocky Mountain wildlife: a review for Montana. [Montana]: Montana Chapter of the Wildlife Society.
Web Search Engines for Articles on "Green Swordtail"
Additional Sources of Information Related to "Fish"

Take us with you!

Look for this PDF icon as you search and browse. Click it to build a custom PDF with species shown on that page or for all the species within that taxonomic level. To create your own list of species, use the PDF Creator tool at the bottom of the Advanced Search page.

Here's some links if you want to download a whole group.

Dragonflies / Damselflies

Ferns and allies

Conifers

Flowering Plants (Dicots)

Flowering Plants (Monocots)

Citation for data on this website:
Green Swordtail — Xiphophorus hellerii. Montana Field Guide. Montana Natural Heritage Program and Montana Fish, Wildlife and Parks. Retrieved on February 21, 2026, from https://FieldGuide.mt.gov/speciesDetail.aspx?elcode=AFCNC06010