So, for structure, so far I have added one large mesquite stump with 4x4" holes cut into it.

And I welded up some steel wheels and old pipe.

I placed these and one more on the slope straight down from the tree that I left in the pond. Eventually, that will be in the center of the pond. Right now I'm working on some floating structure for the minnows to lay eggs under. I'll post more pix as I go along.