Over the past couple weeks, there have been several calls on how to control pond algae. Some have put in White Amur fish which help control vegetation, but these fish do not like to eat algae. Another option is to aerate the pond which may reduce algae and some will even rake the stuff out. A very common option is to use copper based products such as copper sulfate.  When used at the appropriate rate, it is a very safe product. However, now is the time fish are spawning and the fish eggs are very sensitive to copper and applying copper sulfate now will kill the fish eggs. If you wait until June, the spawning season should be over, and applying copper based products at recommended rates will not hurt the young fish.