For clarification, my pond is the first body of water. I'm at the top, I'm the first stop for most of this water that pours out of the hillside. The things in the pond all crawled upstream to get there or walked in, like salamanders and our red-legged frog.
When I moved in I spent weeks devising ways to eliminate the invasive carp that were already there. I even scooped out bullfrog eggs to make ecological room for the native, protected red-legged frog and other animals. I bought this property exactly because it is a sanctuary, a refuge for the native wildlife. If I were an irresponsible person, I'd have tossed koi in there like a buck-toothed moron the week I moved in here. You have no idea who you are talking to, so stop pretending you're the police or god. I care about preserving the balance of my forest and wetlands every bit as much as you do, from the sounds of it. I just haven't felt like wasting words on it until now. But since you can't shut up about it, here I have provided a paragraph for you, so you know I'm not a zitty 14 year old with no functional prefrontal cortex. So unless you have something CONSTRUCTIVE, you can drop this nanny business.
I'm trying to find out WHAT native fish I can put in there. How is that not obvious? Yes, I am also toying with other ideas, thinking of what else I "could" do, but those aren't the things I ever "would" do. It's sad that I have to delineate this for you. I COULD put a wels catfish in there. I COULD think about it, write it down, have dreams about going out and feeding it baby chickens. But I never WOULD do that. Wels are European and would eat every salamander, crayfish, and frog in there!!! And it would be ILLEGAL.
So, back the real world where I don't have to walk around saying obvious things. Largemouth bass actually are pretty cool. I might take a small one from the wetlands below and raise it in a holding container, teach it to come up for food, then move it to my pond. That makes the most sense. Just one so it couldn't breed. LMB get pretty big anyway, that's monster enough for me, I think.