Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Filamentous Algae vs. Ocillatoria

Copper sulfate at close to 1 part per million will kill grass carp and trout.

Easily over 100,000 species of algae. Some are susceptible to effects of barley straw and some are not. Proceed at your own risk.
https://www.btny.purdue.edu/Pubs/APM/APM-1-W.pdf#search='barley%20straw'

My neighbor put Karmex in his pond from the advice from a feed store.... ugh
Do you know how long it will stay in the lake and how long will it stay in the fish? Or or they never safe to eat again

Pat - there are a lot of variables as answers to your question. I don't know a lot about the environmental fate of Karmex (durion) in the water.

Karmex in ponds is a very bad idea !!! It can kill trees a long way from the water.

I guess my main question is, are the fish safe to eat or is like a nuclear test site. I had heard that it has a half life of many years......

Pat, I doubt if you'll get any answers to your question. Instead I'll pose another question.
How many chemical manufacturers would register one of their products for an obviously efficacious type of treatment, IF knowingly endorsing such treatments might pose a chronic health-liability to the manufacturer? Think asbestos...
Ultimately, (IMO) this is probably why DuPont never pursued an EPA registration for diuron's use in aquatics; and they certainly aren't obligated to explain their decision.
Interestingly, diuron "was" registered in Canada (circa 2006) - albeit briefly - but the label lists very specific exclusions. See below.

Kelly thanks for the information, I'm hoping that it doesn't last to long