Asked August 11, 2019, 3:49 PM EDT

There is some algae, green in color, in my pond. How do I know the difference between blue green algae and the "good" green algae? The type I see is fibrous. Will the presence of blue green algae kill frogs? The water is 48 degrees F and gets 9 gallon a minute from a flowing well. Thank you.

Chippewa County Michigan

1 Response

Hi there,

Apologies for the delay in my response. I was out of the office for a while.

Anyway, this is not an area I have much expertise in. However, I did find this resource from the Minnesota Pollution control agency.


This site includes a link to a document for some simple (although not fool proof) methods for testing your algae to determine if it is blue-green or another variety. Typically a for sure diagnosis requires a high powered microscope and an individual with expertise in identifying algae. It should be noted that blue- green algae is not the most common type of algae and there are many other more common types that can bloom as you describe.

In regards to toxcicity, not all blue-green algae produces harmful toxins, but many do. The toxins can be harmful to a wide variety of organisms including frogs.

Best of luck!