Don't panic!
Carol's problem, if I'm reading this right, is having to protect her
fish and dealing with lots of baby fish.
Most folks don't see the predators that Carol sees. In Arizona you
won't have water snakes and bullfrogs and snapping turtles.
Also you may not see as many herons and kingfishers that Carol
sees as she is out in the a more rural area. I see them in my
suburb but only a couple times a year. And mileage will always
vary.
I am the original lazy ponder. I don't filter, I don't mind predators.
I have a large volume of water to a small amt of fish and let
plants do their job. Basically the way a natural pond works.
A natural pond *will* fill in over time so we backyard ponders
will have to scoop it out from time to time but we will let that
chore go for a while (as long as we keep a hole open in the
ice). Fish are only part of the whole pond thing for us. We
love the frogs, turtles, birds that visit, squirrels that stop by
for drinks. We like the sound of the water and the waterlilies
and dragonflies.
You can be a lazy ponder or you can fall for koi and get
really carried away - they are amazing and I can see how
people can really structure a pond for them.
All in what you want to do.
k :-)