Net before the fall, not during it
The single most valuable autumn job is also the most time-sensitive: stretch a fine net over the pond before the trees around it let go. Leaves that reach the water sink, rot and spend the winter releasing nutrients and gases under any ice that forms, and no amount of spring cleaning fully repays an autumn of neglect. Fix the net taut, pegged beyond the pond's edge, and raised at the centre on a float, a cane frame or the plants themselves, so caught leaves rest above the surface and dry light enough to lift off in armfuls rather than stewing in a sagging hammock of wet leaf soup.
Give the pump and pipework their annual inspection
While you are at the water, work the machinery over. Lift the pump, clear its intake cage and rinse the pre-filter foams, and check that flow at the waterfall or return is what it was in spring; a slow decline now becomes a dead pump in the cold. Run an eye and a hand along exposed pipework, unions and the skimmer box for splits, perished seals and blockages of leaf mush. Autumn is the last comfortable month to fix any of it with your hands in the water, and a pump serviced now is one you will not be rescuing from under a net in the rain.
Cut the plants back before they collapse
Marginal plants and lilies finish the season by dying back, and every yellowed stem left standing is future sludge. Cut lily leaves and spent stems back to the crown as they yellow, take marginal growth down hard, and lift the cuttings out in a basket rather than dragging them across the pond. Remove blanketweed in handfuls while you can still see it. The aim is a pond entering winter with as little dying material in it as possible, because everything organic left behind spends the cold months decaying into the water the fish must live in.
Keep skimming through the fall itself
A net stops most leaves and none of the small stuff: seeds, blossom debris and the leaves that sneak under a lifted edge all still arrive. Walk the pond daily during the heaviest weeks with a hand net, clearing the skimmer basket and lifting whatever the net has caught before it mats down. Daily minutes beat a monthly dredge, and the walk doubles as a fish check while they are still active enough to show you how they are going into winter.
Leave the pond tidy, fed-down and watched
As the water cools, pond fish eat less and their leftovers pollute more, so tail feeding down with the temperature rather than by the calendar, and stop when the fish stop asking. Then record the state you left things in — pump cleaned, net on, plants cut — so spring-you knows where the season ended. KinsLe Care Teams can hold that whole autumn sequence as a seasonal duty with each job named, raised early enough in the season that the net beats the leaves instead of chasing them.