I have a 1 acre pond that I cleaned out and completely reworked 2 Years ago. I have a healthy stock of bream and bass.
North Louisiana. It has been cloudy all spring and after adding well water for 48 hours last week a skim developed that looked black Lima an oil slick. Then the skim turned greenish brown. I can not see more than 4” deep in the pond.
Any ideas??
I can’t attach photos.

Just wanted to welcome you to the forum Brian a.

I have no experience with well water in a pond so can't help much but I have heard others say it is a good idea to somehow expose the well water to the air (in a spray or water fall or something) before it enters the pond. Well water us usually mostly devoid of O2 so putting the water directly into the pond without some aeration does not help the pond O2 situation.

I suspect you have some minerals thing going on, but someone will come along with actual knowledge of well water to help.

Yep, well water is rarely oxygenated. Shoot it into the air or run it over some baffles prior to it getting into the pond. No idea what causes the oil slick. Assume that you have had the water tested for safety.