Summer Fish Kill

The first order of business in restoring the pond is to determine why the fish died. My root cause analysis has led me to one conclusion. Lack of oxygen is the most common cause of summer fish kill here in the Midwest. This information comes primarily from the Indiana Department of Natural Resources found at http://www.in.gov/dnr/fishwild/fish/fishing/faqpond.htm#avoid. Based on information from this site, I believe that the extreme dry stretch we had last summer led to a huge algae bloom. This algae bloom limited the amount of sunlight that could get to the plants, which restricted their ability to generate oxygen. At this point, the only oxygen in the pond was being generated by the algae. Being concerned about the amount of algae on the pond, I treated the algae with a healthy dose of copper sulfate. This quickly turned the algae brown and it began to decay. Now there was no oxygen producing plant life in the pond, in fact the algae decomposing was actually absorbing oxygen. The fish already being stressed from limited oxygen and extremely warm surface temperature, died only a few days after the algae treatment.

The next activity will be to determine the best way to prevent this from happening in the future.