Lay a few large empty pots on their side for the fish to hide in during the winter. Fish do not like being in the wide open.
Store your submersible pumps in a bucket of water and move them where they will not freeze. If they dry out the gaskets will fail and you will need a new pump come spring. You can leave it in your pond if your pond is deep enough.
Once you have completed the fall maintenance, and before the leaves begin to fall, put bird netting over the pond to collect the leaves. It will save you a lot of work in the spring and improve the health of your fish. You can purchase it at any hardware store or nursery inexpensively. If you slope the netting from the middle to the outside of the pond you can collect the leaves from the edge of the pond. If you leave the netting flat across the pond it will sag into the water requiring you to clean it more often and you may not be able to reach to the middle of the pond.
When the temperatures begin to cool (mid September and October) it is time to prepare the pond for winter.
As the temperatures begin to fall reduce the frequency of feeding and once the water temperature has stabilized below 45° F stop feeding your fish. If you continue your fish cannot digest what they eat and they will suffer.
Clean the pond bottom of sediment and other dead materials as this is the home of parasites and diseases that will hurt your fish in the spring.
Once water temperatures drop to below 50° F you can cut back the pond plants and set them in the pond bottom. Leave the cattails and bulrushes as they will help in gas exchanges during the winter.
Tropical plants should be moved indoors before the first frost (except for tropical water lilies which need on or two hard frost before being moved indoors).