In the last 24 hours thousands of bluegill fry 1/2 to 1 inch have appeared floating dead on the surface of the 14 acre lake we live on. I'll give some of the history of the lake without trying to write a book so please bear with me. This lake is located in northwest Indiana in a private community and has 64 homes located on it. It has an average depth of 4-5 feet with deeper areas to 8'. The history of the lake is that it had been victim of run off from golf coarse and also for many years the community did not have a phosphorus fertilizer ban but one was instituted 5 years ago. The lake was loaded with organic sediment and for most of the summer months the lake was unusable because of dense filamentous & horse hair algae growths. Aeration was added to the lake 4 years ago but the community manager at the time thought he knew more then those who designed the systems and instead of installing two vertex systems 7's in the lake he only had one installed. Of coarse the systems was not able to properly aerate the lake because of the shallow depths although water quality improved the algae problem still existed and the community spent thousands a year treating the lake to try to control it with little or no results and of coarse increasing the volume of organic material to the lakes bottom. Well last year the powers in control in the community were replace with new individuals who were willing to listen to those who know and changes took place. This spring an additional vertex 7 system was installed and the results were dramatic. Virtually no filamentous algae growth exist on the lake, areas were last year you couldn’t' get your boat into because of the build up of organic sediment are now deep enough. The fish population has exploded and every where you look you see million of blue gill and bass fry, the lake always had a healthy bass population but it was impossible to catch them because the lake was weed choked, now 5-7 pounders are common catches. The first thing we did notice after the second system had been working for a month was that the water clarity changed dramatically, we use to dye the lake with black & blue dye every 24 - 30 days to limit the light penetration. After the 14 point 28 head system had been operational for a month the water became almost coffee (no cream ) colored and when the supply well (very high iron level) was turned on because of a lack of rain, we experienced the red cloudy condition and oily type of sheen that is described by others in the "water quality" discussion. The last 48 hours we had some heavy rains, the type which don’t last long but the sky just seems to open up. We noticed the dead fry last night in one area of the lake close to a drainage ditch and also a yard were the property owner still likes to fertilize his lawn and apply various other “lawn” treatments. This morning I went out and the dead fry were scattered all over the lakes surface but at the same time you can see millions of fry smaller and larger swimming everywhere. Is this fish kill related to the heat conditions, could the heavy rains have washed in fertilizers or lawn weed killers? Or is this just natures way of thinning the population out so that there is enough food for all the fry? What water test should we take what should we look for first? I guess there are a lot of variables but any input or comments are appreciated.