This looks like a good place to compare notes about ponds with a bunch of knowledgeable folks. I'm in central Michigan. Dug a hole in the front yard garden 10-12 years ago and dropped in a 165-gal hardshell liner. It didn't take long before the green frogs moved in. I added a half dozen 2-inch panfish and they prospered (and reproduced) for a long time. Haven't had fish for a while but the frog population is going strong. Right now we have a dozen or so hibernating in the muck, lilypad roots and leaf litter at the bottom. I've been pretty amazed that the pond has more or less self-maintained a stable and balanced ecosystem that doesn't require much intervention from me. I scoop out excess leaves in the fall and change the filter pads every now and then on the 550-gal pump that's housed in a box at the bottom of the pond. In the summer it feeds a waterfall. In the winter, I convert it to a fountain to keep the pond from freezing over and keep up the oxygen levels. So that's my story. Nice to be here!