Ideas yes. Specifics no.

I assume you have a pretty good well to almost fill a 3 acre water hole. That also indicates the amount of the leak since you can only stay even. Six ft. over 3 acres is a whopping amount of water. My immediate thought is to cancel or delay the fish order. I personally think you will have to let it drain until you find the leak. I don't think it will improve.

Where in South Texas are you and what type of soils are you working with?

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 Grandpa