Jambi is correct re the oaks and tanins. That stuff is lethal. When my approx 3 acre pond was built, we cleared some oaks. I had them pushed into a pile in the bowl for fish attraction. We got some big rains and the pond filled about 2/3. I stocked fish. Then the water turned black and everything died. I pumped for a couple of weeks. Then let Texas summer sunshine dry everything. Then, after awhile, we got a decent rain and it happened again. I pumped again. Luckily, we didn’t get any rain for a couple of months. Now, 30 or so years later I’m praying for rain.No tanin problems.

It's not about the fish. It's about the pond. Take care of the pond and the fish will be fine. PB subscriber since before it was in color.

Without a sense of urgency, Nothing ever gets done.

Boy, if I say "sic em", you'd better look for something to bite. Sam Shelley Rancher and Farmer Muleshoe Texas 1892-1985 RIP