How much "Winterizing" you have to do depends on your climate.
Every year we have people in warm climates winterizing too early and too much for their climates. Because they read posts by those in very cold climates and think they need to do it too.
For example: here in Portland OR I remove tropical plants that will freeze and cut back the hardy plants.
My pump/waterfall run 24/7/365 and I don't need a de-icer of any kind. The waterfall keeps a hole open if there is an ice cover which doesn't happen very often.
IF I feel like it I try to get some of the organic debris from the neighbor's trees out of the pond as it is yucky looking. This year I did this and I burnt up my Shop Vac. Must find another solution. We are talking pine needles and pine cones by the pound here. The amount I removed would fit in two 5 gallon buckets. The fish don't seem to care one way or another (this pond is almost ten years old) but I hate looking at the stuff on the bottom.
Jarch, that is a very nice pond!
Barb, I am feeding a fall/spring food daily and will continue as long as it is sunny here. Mostly, I want to see the fish, I added some new ones and we've had raccoons several times recently. (we didn't realize ground wire to electric fence was broken)