Remove the Leaves
Once autumn has taken hold and most of the leaves have fallen, take the time to remove any debris that has settled in your pond. Leaves decomposing underwater give off methane gas which can create an unhealthy environment for fish. After cleaning your pool, put a thin netting over it to catch any leaves or straw being blown around your yard. Or rake a large area around your water feature to help prevent this.

Don't Forget the Fish
In warmer regions of the South you may still be enjoying your watery oasis, but in colder areas you could be looking at a frozen ice puck. Cold water makes fish sluggish; with their lowered metabolism, they seem as though they're swimming in slow motion. Stop feeding them once the water temperature dips below 45 degrees. The plant and bacteria growth that breaks down fish waste is not available in frigid water, and the declining water quality can be detrimental to fish.

If you have fish, live in colder regions, and your pond surface freezes for more than 10 days, you should make a hole in the ice to release trapped methane. Never break the ice using a hammer; the shock waves can kill fish. Pour boiling water on the pond's edge to melt a hole to release gases.

Keep Frigid Temperatures at Bay
A submersible pump equipped with a foam jet (bubbler) set to discharge water an inch or two below the surface can be placed in the pool's center to move warmer, deep water to the top. This prevents the surface from freezing. If you leave the pump on throughout the winter, check it periodically to make sure debris doesn't stop up its intake. Also check after power outages to make sure ice hasn't formed over the discharge pipe.

Plant Protection
Tropical water lilies will overwinter in warm regions that don't receive killing frost. If your hardy lilies are sitting on bricks or a plant shelf, drop them to the bottom of the pool where they can avoid being frozen solid.

The South is lucky enough to have occasional warm days through the winter months. Use these pretty days to clean your water feature. Although your pond may look lifeless at this time of year, it may be the only source of water for birds and squirrels. Don't turn your water feature into a swamp this winter. The neighbors and the critters will thank you.