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Oxygen Weed

Scientific Name

Lagarosiphon major (Ridley) Moss (ITIS)

Common Name

Oxygen weed, Lagarosiphon, African elodea, curly waterweed

Native To

Southern Africa (Bickel 2011)

Date of U.S. Introduction

Not introduced

Means of Introduction

Spread through the world by the aquarium trade (Bickel 2011)


Has invaded New Zealand and Europe. It can inhabit freshwater lakes, dams and slow moving streams. Forms dense mats that block sunlight, thereby killing native aquatic plant and animal species, which could rival the harmful effects of hydrilla (Csurhes and Edwards 1998)

Current U.S. Distribution

Not currently established

Oxygen weed
Image use policy

Oxgen weed


Photo by Rohan Wells; National Institute of Water and Atmospheric Research

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Federally Regulated

  • Noxious Weeds Program

    • USDA. APHIS. Plant Protection and Quarantine.

    • Includes species listed as a Federal Noxious Weed under the Plant Protection Act, which makes it illegal in the U.S. to import or transport between States without a permit.


  • YouTube - Impact of Non-Native Species in Irish Water Bodies

    • Google. YouTube; RTÉ Ireland. Eco Eye.

    • This beautiful episode opens on Lough Corrib at sunrise. Anja sees first-hand the devastating and costly impacts of a new arrival to an existing ecosystem, Lagarosiphon Major a pond weed has taken hold in the waterbody. Part 1 of 4

Selected Resources

The section below contains highly relevant resources for this species, organized by source.

Federal Government
International Government
State and Local Government