• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
  • Texas A&M Forest Service
  • Texas A&M Veterinary Medical Diagnostics Laboratory
  • Texas A&M AgriLife Extension Service
  • Texas A&M AgriLife Research
  • Texas A&M College of Agrculture and Life Sciences
A Diagnostics Tool for Pond Plants and Algae
  • Menu
  • Home
  • Identify a Plant
  • FAQs
    • FAQs List
    • Do I need a permit?
    • Glossary
  • AquaExtension Events & Learning
  • Videos
  • Get Help

Filamentous Algae

Spirogyra, Anabaena, Oscillatoria, Lyngbya, Pithophora spp., etc.

Filamentous Algae being pulled to show filaments
filamentous algae diagram

filamentous algae cluttered by pond bank

filamentous algae clinging to rock
filamentous algae on rocks under water

What is Filamentous Algae?

Physical Characteristics

  • Single algae cells that form long visible chains, threads, or filaments
  • Filaments intertwine forming a mat that resembles wet wool

Where Does it Grow?

Filamentous algae starts growing along the bottom in shallow water or attached to structures in the water (like rocks or other aquatic plants). Often, filamentous algae floats to the surface forming large mats, which are commonly referred to as “Pond scums.” There are many species of filamentous algae and often more than one species will be present at the same time in the pond.

Pros and Cons of Filamentous Algae

Filamentous algae has no known direct food value to wildlife. Submerged portions of all aquatic plants provide habitats for many micro and macro invertebrates (i.e. bugs, worms, etc.). These invertebrates in turn are used as food by fish and other wildlife species (e.g. amphibians, reptiles, ducks, etc.). After aquatic plants die, their decomposition by bacteria and fungi provides food (called “detritus”) for many aquatic invertebrates.

How to Manage This Plant
Plant Glossary
Online Courses

AquaExtension Newsletter

Receive updates on upcoming webinars and newly published materials.

Sign Up Now

Newsletter Archive

Upcoming Events

Jan 21
Featured Featured January 21 @ 6:00 pm - October 21 @ 7:30 pm CST

2025 Aquatic Webinar Series Bundle

Jul 8
Featured Featured 12:00 pm - 1:30 pm CDT

Sizing up a Pond For Realtors & New Landowners

Jul 22
Featured Featured 6:00 pm - 7:30 pm CDT

Pond Management Myth Busting 101: Water Quality Webinar

View Calendar

Search for a type of plant

Hire a Professional Contact Your Ag & Natural Resource Agent Aquatic Plant Nurseries Aquatic Herbicide Tables
Texas A&M AgriLife Extension Service
Texas A&M University System Member

Follow Us

  • Facebook
  • Instagram
Click to view full permission and citation information

Aquatic plant photographs were provided by David Bayne, Jim Davis, Kelly Duffie, Billy Higginbotham, Michael Masser, John Clayton, Chetta Owens, Diane Smith, Joe Snow, Don Steinbach, Bridget Robinson Lassiter and Peter Woods.

You may use these photos, so long as you give credit to AquaPlant.

  • Compact with Texans
  • Privacy and Security
  • Accessibility Policy
  • State Link Policy
  • Statewide Search
  • Veterans Benefits
  • Military Families
  • Risk, Fraud & Misconduct Hotline
  • Texas Homeland Security
  • Texas Veteran's Portal
  • Equal Opportunity
  • Open Records/Public Information