* Keep it Clean - Make sure your watergarden is clean for the long winter dormancy period. Install a pond net to keep leaves and debris out of your pond. This is very important, as the more leaves and debris that wind up in your pond the worse it is for your fish. As the leaves get saturated with water they sink to the bottom where they start the rotting process. As they rot they are turned into nitrates by nitrifying bacteria. To refresh your education on this see the nitrogen cycle.
As the water temperature starts to drop your fish’s metabolism starts to slow down getting them ready to go dormant for the cold winter. This dormancy period is a weakened state that makes your fish more susceptible to disease. With a dirty pond and high nitrates there is going to be a higher risk that you will lose some fish over the winter! If you spent a lot of money Koi, or just a pond hobbyist who loves their little goldfish, this simply cannot be allowed to happen.
Remove your pond netting before snow comes and clean out any remaining leaves and debris. Snow and ice can accumulate on your netting and collapse and tear it up making it useless. If you want to leave your pond netting in place all winter be sure to install some supports for it should it become heavy from freezing sleet or lots of wet snow. You need to decide for yourself if your netting can withstand some weight.
* Care of Pond Plants - As soon as your plants such as floating water hyacinth, marginal plants bog plants, and lilies start to look brown you need to take action. Get the hyacinth out of the pond. Cut back your marginal plants and lilies. Cut them right down to the base of the soil. They will come back in the spring. Leave water lotus alone, cutting the plant can cause the tuber to rot.
If you have tropical plants in northern climates they need to be out of the pond before the first frost. You can store your floating and submerged plants (like water hyacinth and anacharis) in a plastic kiddies' pool of water in the basement or garage. If there is no natural light you should hang a hydroponic grow lamp over the plants and run it a few hours each day with a timer to keep them alive. Most people in the northern climates just order new floating and submerged plants in the spring and avoid the hassle of wintering them over inside. Depending on your agriculture zone, your floating and submerged oxygenation plants may winter over fine or die.
Oxygenator plants are not true hardy species, or true tropical species, but somewhere in between. Most people classify them as subtropical. If you are a new watergarden owner you will have to find out by trial and error if your agriculture zone will winter over all of your plants. There are too many variables for us to say whether your local zone is OK.
* Poisonous Gasses - If poisonous gasses are allowed to accumulate under the ice and not vent away to the outside air it can kill your fish. This is known as “Winter Kill.” Install an aerator on the pond bottom and the bubbling will keep a hole open, or use a pond heater to keep a hole in the ice for an air-gas exchange. Either will work fine. It is a matter of personal preference.
*Aerators or Floating Heaters? - Most people like to use a pond aerator simply because it can be used during the other seasons as well to increase the oxygen content of the water. Aerators also to create a more efficient cleaning cycle by bringing up temperature stratified water, which doesn't hold oxygen well, at the pond bottom to the surface. Aerators are more energy efficient than pond heaters. In just about all cases we here at Crystal Creek Pond Supply recommend using an aerator to keep your water open during the winter months.
* Stop Feeding the Fish - Stop feeding your fish when your ponds water temperature reaches 50-55 degrees. If you want to continue to feed in the 50-55 temperature range use Koi food especially for cold weather conditions. Do not under any circumstances feed below 50 degrees as this food will more than likely be trapped in the fish’s digestive system all winter.
* Disable the Pond Filter - Remove all the filter pads or filtering material (filter ribbon or bio-balls) from the filter. Clean it, dry it out well, and store it for spring. Running the filter in the winter is useless unless you are running it for extra water aeration without the filter pads. Filters pads don’t work well in the winter because the active bacterium, which eats up the bad stuff, become dormant at low temperatures.
