Trim all of the perennial aquatic plants that begin going dormant as the weather cools. Your aquatic plants aren't dying, but they may turn yellow or brown as they go dormant. You should remove the yellow/brown soft leaves to prevent decaying debris from building in the bottom of your pond. This is actually a good habit to get into all year long. This simple trick will make your pond cleaning responsibilities much easier.

The only plant that we don't trim in fall/winter are the floating water hyacinths. This plant depends upon it's roundish bulbs to keep it afloat. If you trim the bulbs late in the year, the plant may sink and rot. Instead, wait for spring. When the water hyacinths make 2-3 good sized new green bulbs early in the season, that is the time to trim off all of the dry or rotted portions of the plant. Just rip off the old material, leaving several green bulbs and toss the plants back in the water.

This is also a good time of the year to clean your biological filters and service skimmer boxes and pumps.

Check all wiring, pump and filter connections and clean or replace the pump screens. As an absolute minimum, you should have mesh screen bags around all pump inlets to keep snails from crawling into the intakes. Snails, especially the small Ramshorn type, follow the flow of water, die, and their shells compact around the impeller intakes. This blockage can easily burn out that very expensive pump.

In the north, you may want to use a pond heater to keep a breathing hole in the ice.

Make sure everything related to the pond is in good working order. Order supplies needed for next season, including a new UV bulb. You may still see visible blue light coming from the bulb, but the intensity of the UV rays drops dramatically after about 8 months of use. It's better to just replace the UV bulb every spring. eBay is a good place to find the supplies you need. We've had good luck buying consummable items there and in fall you are not in a hurry, so buying from Chinese suppliers can often be worth the wait. Ask around and find out what luck other ponders have had buying online and which suppliers they use. Our own experience shows that a lot of items imported from Asia are junk, but we occasionally find a great supplier that makes quality equipment at good prices. Think iPhone, they all come from China, and have brightened our lives. When American engineering gets coupled with careful quality control, excellent products can be produced.

You should also buy pond spikes or fertlizer tablets so you have them on hand when dividing plants in the spring. The new fabric planting bags are one of our recent finds, and after a year of use, they seem like a great idea.

Fall is a good time to watch for sales at nearby nurseries.