Blue-Green Algae

Floating Filamentous Cyanobacterium (Blue-Green Algae)

Blue Green Algae

The most commonly occurring algae is, in fact, bacteria.

Not algae.

Previously called ‘Blue-Green Algae’ it shares many traits with algae (eukaryotic cells) including appearance.

Cyanobacteria fossils date back 3.5 billion years, making these prokaryotic cells the oldest known fossils in the world. It may be interesting to remind you, the oldest known rocks on earth are 3.7 billion years old.

Find Which Strand You Have:


Blue Green Algae
Appears rapidly, initially appears white and soapy, then becomes like spilled paint or pea soup. It creates a smelly blue-green oil scum at the surface.


Blue Green Algae

Commonly found growing with Microcystis (both can cause skin irritation). Has an appearance of tiny grass clippings floating in water.


Blue Green Algae
Appearance almost identical to Microcystis’ pea soup coloring, except Anabaena is filamentous and doesn’t migrate. The microscopic visual difference is a thicker cell wall than Microcystis. Occurring in phosphorus rich waters, Anabaena produces toxins which can kill pets, wildlife, and livestock.


Blue Green Algae
Split into floating mats or attached to rocks, Oscillatoria appears in colors of dark blue-green, dark red, brown, green-black, or purple. May show an oscillating movement. Can produce toxic microcystis in certain strands.

(Attached) Nostoc

Blue Green Algae

Forms large (dark green, yellow-green, or blue olive green) jelly-like balls or mats. Also called freshwater grapes, Nostoc is generally non-toxic but under certain conditions can produce liver toxins.


Methods of Removal and Treatment


Mechanical Control (environmentally safe):Blue Green Algae

Pumping Surface Scum

AeratorBlue Green Algae

Raking or Sifting

Biological Control:

-Microbial Products (environmentally safe)

-Grass Carp (disease free and sterile)

Blue Green Algae Weed Razer, Kleer, KL001, non-toxic, all-purpose planktonic algae control product

Chemical/Physical Treatment:

Blue Green Algae Weed Razer, Cutrine-Plus, Algaecide


Copper Sulfate (not biodegradable)

-Barley Straw

-Phosphorus Inactivation Products

-Shading Products~ dyes limit sunlight

-Endothall-amine salt

-Sodium Carbonate Peroxyhydrate


Read More:

Field Guide to Scum

Weed Razers