An annual cleaning of your pond is recommended to remove debris and decomposing organic material. Toxins can build up quickly in the garden pond, yearly removal will help keep the pond healthy. Total cleaning means removing all plants, all water, all fish and giving the pond a good cleaning.
How to Clean Out a Garden Pond
Put some pond water in a large bucket or box. This will hold your fish while you empty the pond. If you will be more than 5 or 6 hours, place a pump or air-stone in the fish holding tank. Put the pump in the pond. If you have a sump (a slightly deeper spot) in your pond, put it there. Put the pump inside a milk crate to keep the the bottom debris from clogging the pump.
Stretch out the hose that is attached to your pump so the pond water goes where you want. Usually a vegetable garden or lawn is the best place to empty pond water. Plants love organic matter.
Plug in the pump. If you use an extension cord, keep the ends of the cords out of the water.
While the water is pumping out, take out the plants. Put on your waders now because you have to get in the water to remove the plants.
If you have plants that need dividing, do it now. If not, clean the sides of the pots off, cut all dead growth off, remove all live growth that has grown out of the pot.
Remove submerged vegetation. Ask your helper to clean any debris from it.
Net your fish and put them in the bucket, tank or box you prepared for them.
Wet vac the bottom of the pond. Rinse it with well with your nozzle on the end of your garden hose. Then vacuum it again until it is clean.
Put the debris you have removed in the second milk crate so the heavy water can drain out. Then put it in the trash bags. If you have a compost heap, put the debris in there.
Place the plants back in the pond and start the new water running.
When the pond is about half full, put the fish, box or bucket and all in the pond. In a few minutes the old water temperature and new water temperature will equalize. Release your fish within 15 minutes.
Continue filling the pond.
When the pond is full, put your waterfall pump back in and plug it in. Your pond is clean and healthy for another year.