Any Bend, Oregon ponders ?

I'm new to ponds and could really use some suggestions as to the best way to
prepare my ponds for winter. It does freeze here, but I've no idea if it's
enough to freeze 2 - 2½ ft. ponds solid. (I don't think so, but not sure).

If any of you are from the Bend area (Central Oregon's high desert) I'd
appreciate knowing what all you do or don't do.

I have two plastic liner ponds. One about 6x8x2 and the other about 6x10x2.
In the 6x8 I have 7 fish (3 4" shubunkins, and 4 2" goldfish). No live
plants yet. Just a few plastic lillie pads for fish cover and shade. There
is a waterfall in the larger (upper) pond but it obviously won't be running
in the winter. The two ponds are connected by a small fall out of the larger
into a stream whic obviously will not be flowing in the winter since the
waterfall will not be running. The only pump is an above ground swimming
pool pump that circulates from lower to upper pond - again this too will
have to be turned off for the winter.

Other than not feeding the fish (other than maybe a pinch a week or
something because there is no live food in it) and making sure to break any
ice that forms on the surface so gases can escape is there ANYthing else I
should be doing to overwinter the ponds and fish?

I'd appreciate any pointers.
TIA