I live in upstate NY, right on the lake Ontario shoreline and did my first pond this past year.
My set up is a lot like yours, but much smaller. I have a pre-formed 50 gallon bottom tub, a nine gallon bog filter, then a one gallon weir at the top.
I turned off the pump for the winter and used a tetra pond de-icer to keep the water from freezing. It is only rated at 40 degrees F though, so the water was still pretty cold...
I stocked it with golden white clouds minnows. I wasn't sure how well they'd do, but they just didn't survive, they thrived. There are far more this spring then when I shut it down late last fall.
Here is what it looked like after the winter. Disregard the dumb thumbnail, it's what I do.
And here is after a little bit of work getting it cleaned up. You can actually see a few of the goldens toward the end.