Utah Department of Agriculture and Food

Cyanotoxin Identification

How Do I Know if I Have A Toxic Bloom?


You can’t know for certain unless you have the water tested.  However, look for these differences between cyanobacteria and non-toxic green algae:


  • Cyanobacteria looks like pea soup, an oil slick, or like someone placed dye in the water. Cyanobacteria is potentially toxic under the right conditions (See right).


  • Filamentous (non-toxic) green algae often looks like a mass of green hair on the water (see below).


Links To Other Identification Resources

Field Guide to Algae (from Kentucky)



HAB Home