Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Copper sulfate for fw control and catfish problem.

It appears that you applied a whole-pond concentration of roughly 2 ppm in a single dose.
Bill Cody can better comment on cc's tolerance-threshold to copper sulfate. However, dosing the entire pond at 2 ppm in a single treatment sounds risky to me - depending on your pond's water-characteristics.
Refer to the Environmental Hazards on pg 2 of this SPECIMEN LABEL .