Pond Boss Forums AERATION Systems questions Fry (Fish) Kill

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.

After the first post - I received several phone calls from other residents regarding the fish kill and went to investigate the other side of the lake by the overflow. In that location was 20 + bass over 4 pounds and many other fish of all sizes (bluegill, bullhead, small bass,) all recently dead with still red in the gills and not yet stiff. There were no crappies, walleyes, or muskie -which are also in the lake but we are wondering it those from deeper water haven't floated up yet. What test should we perform? What water sample should we take? We froze several of the fish to send to Purdue University extension for examination. Could it be VHS? Any input or ideas appreciated.

I sent you a PM

While the experts are chewing on this one, I can start by saying that sudden rains sometimes result in "natural" fish kills. The smaller the fish, the more vulnerable they are. It's something to do with reduced oxygen, maybe due to deep, oxygen-poor water rising to replace the rain water as it sinks.

Ted has more knowledge about this subject in his little pinkie than I'll know in my whole life, but I've seen situation in my ponds where the environment within the border aquatic vegetation were significantly different than in the open water. Presumably this was because of plant respiration and plant death caused by a sudden change in water temps, light availability, etc. It appeared to me that the smaller fish were essentially "trapped" in these low DO zones, whereas the larger fish that were beyond the immediate peripheral vegetation escaped harm.

I just came back from the Lake and we have some dead walleyes popping up now, they appear to have been dead for the longest period of time (color washed out and bloating) also I was able to get a 4# bass that was dying when I got there and have frozen him for examination. I also found out that the golf course was treated with a fungicide and liquid fertilizer the day before the rain and our ground was extremely dry and hard so I don't believe much was soaked up. One thought is that we had this flushing driving rain and the material was washed in. Also that since multi-species and sizes of fish were affected it was a toxic poisoning as apposed to the heat or 02 content ,that we are checking but there are 28 diffusers on the aeration system operational. Also is it possible that the Thousands of small fish that died yesterday and were floating were consumed by the larger fish we are seeing die now and they were poisoned. Some of the bass were coming into shore as if they were gasping for air and then went belly up. We are taking water samples and getting the MSDS for the material that was used on the golf coarse.

Fungicides can be pretty toxic, but it would take large quantities to get an LD50.

Good luck!

Hey FK,

I live a few miles from you, and have fished 'your' lakes, my guess is, with the amount of rain that DUMPED on us a couple of days ago, depth of lake, proximity to golf course, etc... IT WAS RUN-OFF!!! I know for a fact, my pond level went up almost 4", with that "soaker" we got. Sorry to hear bad news, has the well been turned on? Has the diffusers been turned off?

I'm sickened to report that I have just come in from the lake and there are dead fish everywhere of all sizes and species. There is not the sound of one bullfrog and the smell is just starting. Yes I know it was run off from a treatment of a fungicide that is toxic to aquatic life and a listed carcinogen in California, and it also contaminates ground water under certain conditions when used as direct by label. All of the information is from the chemicals MSDS it just sickens me. The work that put into this Lake over the last seven years, the time, the frustration and the Lake was looking the best in anyone's memory. All of this trashed because someone was dead set on stopping any fungus on the fairways, ohhhh heaven forbid! I'm so distort, don't know if I should cry, throw up or...
No the aeration system is still running, cn't see if it makes any diferance, the smell will be terrible if we shut them off.

I'm sorry...

Sorry for you loss.

Shallow water - big rain - high temps - my guess is a DO crash. Yes it can happen even with diffused aeration. That is why paddle wheel aerators are used in catfish farms. Diffused aeration is a great method which I support fully. It is not an emergency aeration system - it is not designed for that. When most of the plankton/plants go down in a DO event even a properly sized diffused aeration system can't cure the effect in the few short minutes it takes. They can and often do provide areas of safe haven which fish realize and move toward. You probably have survivors. High fish densities also contribute to situation. Find what caused the plankton to suddenly die and that is most likely the cause. Plant material washing in from a large rain event also contributes to the O2 depletion.

Me too.

I was not able to respond to comments yesterday because I was at work (firefighter- 24 hr shift), but I would like to ask a few question to anyone who could help us.
We are looking for which test to run to determine what did happen. I regards to O 2 depletion, we have several other ponds and lakes which there were no fish kill at all, also that the golf coarse has been been using this fungicide for the last few years. We have a two vertex system 7's in the lake , one of the systems does have to new heads for shallow water - so there are 28 aeration heads operating in this lake. We have not had to treat the lake with any chemicals for weed control all year and the only thing we have been adding is dye to cut down on light penetration.
I'm concerned that if the fungicide caused the kill (Chlorothalonil) that if it is the cumulative in the fish that survived , also if so could the levels had been building up to a point and then pushed over the edge and with the treatment being done before the rain and the sudden influx caused the kill? Are surviving fish contaminated ( bluegill, catfish, walleyes) with the chemical to the point that they should not be eaten if caught in the future? The chemical is a suspected carcinogen and their are several greens that have drainage directly into this lake, (more then other the other lakes) so I'm still very concerned that this is problem.
We are located in northwest Indiana so If anyone could recommend a company or individual who we could contract to assist in pinpointing what the cause was please contact me.
Yesterday the bodies of the larger bass ,8 pounds plus, started to float up and I have to say I was glad I was at work because it would have killed me to see it in person, myself and many others have spent a great deal of time and money restoring this lake. We need to identify the problem so that it does happen again and because of "politics" in the community (golfers vs lakes people) we need to have proof if the chemical was a factor.