I recommended a pond breather before I had a look at the size of pond.
The pond breather needs deeper water.
A couple of things to consider if you want to keep your pond operating through winter -
-How cold for how long does it get where you live?
-What is your frost line at?
-How exposed is your pond to wind?
-If you use a floating deicer or a heater to keep an open water area, you will have a fair amount of water evaporation so you will need to top up the pond with water quite frequently. That could change the water chemistry depending on the difference between the source water and pond water which could create hazardous conditions for your fish.
.