A friend of mine is having problems with algae in his fish ponds which mainly house "koy" fish.

Would placing corn meal in a burlap bag and sinking it in the ponds clear the algae without hurting the fish?

Thanks for the input!

If it is truly algae, yes it will get rid of it. If you use too much, too fast, you run the risk of oxygen deprivation to the fish. See links below for further info:

http://www.dirtdoctor.com/forum/viewtopic.php?t=2349&highlight=algae

http://www.dirtdoctor.com/forum/viewtopic.php?t=1582&highlight=algae