It is most often blue-green in color, but can also be blue, green, reddish-purple, or brown. It generally grows in lakes, ponds, and slow-moving streams when the water is warm and enriched with nutrients.
Concerns: Discolored water, reduced light penetration, taste and odor problems, dissolved oxygen depletions during die-off, and toxin production. Due to oxygen depletion it can cause fish kill. You can become sick if you swallow, have skin contact with, or breathe in airborne water droplets during recreational activities in water that has harmful algae or if you drink water that contains algal toxins.