Your pond takes very little maintenance, much less than your lawn that you fertilize and then mow each and every week. But there are a few things that you can do to keep your pond looking beautiful and your goldfish healthy. Keep an eye on your pond. (As if you didn't already). Watch for changes in water color, water level, fish lethargy or pump slowdowns. If you see anything unusual, deal with it as soon as you can. But usually, following these few tips will keep any disasters at bay.
Weekly Tasks
You visually marked where your normal water level was after your pond was built. Check the water level weekly--if it has dropped due to evaporation, top it off. Add a dechlorinator if you add more than 10% of the total volume of water. If it has not dropped, and you have some time, pump about 10% of the water into the surrounding vegetable or flower garden and top off the pond. The water is a great (and free) fertilizer and the water changing deters chemical buildup that can eventually corrode the pump or foul the water.
Check the bottom of the pond for decaying vegetation and remove dead plants, leaves or other organic matter. Dead and decaying plant material can foul the water and kill the fish. Net any debris out and put it in your compost pile or use it as direct compost in your flower beds. Remove childrenís toys, tennis or golf balls or used champagne glasses at the same time.
Monthly Tasks
Fertilize your water lilies with a product made for aquatic plants. Follow the manufacturer's directions for application. Fertilize the lilies from the time the leaves reach the surface in the spring, for us, in New Orleans, thatís in April or May, until the lilies go dormant, usually about the end of October. Most likely by September or October, your lily leaves are getting smaller and not they are not blooming as much. Lilies react to the length of days and nights. As daylight gets shorter and nights get longer, your lily knows winter is coming.
If you have a prefilter with your pump, clean it at least every month. During the hot part of the summer and if your pond is in full sun, clean it more often. If the filter has a foam rubber component, run water through it until the water runs clear. Do not squeeze or wring it out. If it is a biofilter, donít clean it except yearly. If you must clean it more often, you are overfeeding your fish or your bio load is too high. Reduce your fish population. Often when I am cleaning a biofilter, I will rinse it in pond water. If I use water from the hose, I will use specially formulated pond bacteria to kick start the bio process again.
Yearly Tasks
Remove all of the fish, plants and pump out the water. Lightly scrub the bottom and sides of the pond with a brush--do not use chemicals or soap.
Refill the pond, dechlorinate, replace fish, divide plants, repot and replace. Save some of the old water to store the fish in while the pond is being cleaned. I use a big blue storage box that we might also use for blankets, sweaters or lego toys.
Put the fish in plastic bags in the old water. Float the fish on top of the newly cleaned pond until the water in the bag and the water in the pond are the same temperature. Late February or early spring wherever you are is a great time to do the yearly cleaning. Make sure the temperature of the water is above 55 degrees, so you don't disturb all those fish in torpor too soon. If the clean water temperature differs more than a few degrees from the old pond water, you may lose all your fish.
All this said, I live in New Orleans, where hurricane Katrina destroyed my house. One year after Katrina hit, the old house was demolished, I had moved into the new one and was ready to move my pond across town. I had not looked at my pond for over a year. I expected a foul, nasty mess. I found about 8 inches of water in the pond, about a bushel of submerged vegetation and 6 live goldfish. So routine maintenance or not, cleaning or not, ponds may not thrive on benevolent neglect, but they continue to be a healthy ecosystem.
