As the days grow shorter and the temperature falls, there are a few tasks that you need to do to get your pond ready winter. If you have koi or goldfish in your pond, it is essential to close your pond properly  to help ensure they survive the long winter months and are alive and healthy next spring. Here are some tips to help you winterize your pond.

We have all the Fall and Winter Pond Supplies you need to prepare your pond for the winter. You might also want to look at How To build a Winter Pond Cover

Cold winter weather can sometimes hit suddenly, so it is important to get your pond ready for winter early, in case a sudden cold snap catches you by surprise.  If not properly closed, the freezing winter temperatures can damage pond equipment.  

In most cases, it is best to remove your pump from the pond, to make sure it does not get damaged by freezing. Clean it thoroughly and store it in your garage or shed for winter. If you have a direct drive style pump (not a magnetic drive or asynchronous pump) then it should be stored in a bucket of water and protected from freezing. This helps to keep the seals moist. If you have a magnetic drive or asynchronous pump they can be stored anywhere dry. When spring returns, your pump will be ready to install. 

BioFalls and waterfall style filters can be left in place but should be drained of water. Some ponds have a check valve installed in the tubing, usually near the pump or in pond skimmer. These check valve prevent the water in the waterfall filter from draining back down into the pond or skimmer. These check valves should be removed because they will prevent the waterfall filter and tubing from draining. If water freezes in the tubing, there is a good chance it will split the tubing. It is also best to remove the filter pads and bio-media, clean them thoroughly and store somewhere dry.

In areas with milder climates, some people prefer to leaver their pumps and waterfalls running throughout the winter. This helps to keep a hole in the ice and maintain oxygen levels in the winter.  

Pressurized Filters need to be drained of water and stored inside somewhere dry. It is best to remove the filter pads and bio-media, clean them thoroughly let them dry and then store them back inside the filter. Make sure not to lose the O-rings or gaskets, put any small or loose gaskets in a ziplock bag and store it in the filter so they are easy to find in the spring. 

Gravity / Flow Through Filters should also be drained and thoroughly cleaned. These filters can be disconnected a stored inside for the winter, but can also be left outside for the winter. Larger filters might be difficult to move, or yo may not have enough space to store them inside. Make sure to leave the drain valve open in case any water gets in during the winter. 

UV Lights should be disconnected, cleaned and stored somewhere safe where there is no chance of them falling and breaking the quartz sleeve and bulb. Again, keep track of the gaskets.

We often get asked by customers if they should leave their waterfall running all winter. Here in central Ontario, I recommend that you shut down your waterfall and remove the pump from the pond. Temperatures here can get quite cold causing ice more and more ice to build up around waterfalls and streams. In cold snaps ice ‘dams’ can form which can block the water returning to the pond, diverting over the edge of the liner and out of the pond. This will drain your pond and you may not even realize it.

This has happened to some of our customers. In one case, our customer decided to take a closer look at their pond after a few days of very cold weather. When they looked through the hole where their de-icer was, they noticed the pond was almost completely empty and their fish were frozen. It turns out, the pond had a fairly thick layer of ice, and it held its shape even after draining. Everything looked normal from a distance, but if they didn’t take a closer look, they wouldn’t have known anything was wrong until the warmer temperatures weakened the ice.

Another reason to shut down your waterfall is that you can actually chill your pond even more than normal. Exposing the pond water to the much colder air as it passes over the waterfall, will cool the pond water down more and cause more ice to form. We will often leave our waterfalls running into early December so that we can get some nice ice formations. 

Insulating the pond, is another way to prevent a thick ice layer. If your pond is not too large, you can insulate it by laying boards across the pond, cover them with plastic, and insulate it with Styrofoam, a thick layer of leaves, straw or anything else that would provide insulation.

Goldfish and koi are very hardy fishes; they can survive water temperatures as low as 0°C, which means they can survive in the pond during the winter as long as it doesn’t freeze solid and they have adequate water quality and oxygen. To help ensure healthy fish in the spring, follow these steps:

• Begin feeding  a Cold Water Fall Fish Food such as Aquascape, Microbe-Lift or Hikari once the water temperature falls below 18 °C / 65 °F. Start by mixing a bit of the Fall Food with their regular summer food, then gradually increase the amount as the temperature decreases. Once the water temperature falls below 15 °C / 59 °F you should only feed a cold water food. Gradually reduce the amount of food that you feed as the temperature drops. Stop feeding once the water temperature consistently remains below 9 °C  / 48 °F. It is important not to feed fish below this temperature, their metabolism is so slow that their digestive system basically shuts down and does not process food.  At low temperatures, food  can become  trapped in their gut for long periods of time causing serious problems. Always use a Pond Thermometer to check the water temperature.
• Remove tree and plant leaves from the pond. Leaves and other organic matter will continue to break down through the winter months causing poor water quality (elevated ammonia and nitrite) and low oxygen levels in the pond. The easiest way to do this is to prevent leaves from getting into the pond by covering the pond and waterfall with Pond Netting. Also remember to remove any tropical plants like water lettuce or water hyacinths and trim any dead leaves from water lilies or marginal plants.

• Remove sludge and organic debris from the bottom of the pond. It is important to remove organic matter from the pond because any tree leaves or twigs, dead algae, or plant material that remains in the pond, will slowly break down, consume oxygen and reduce water quality during the winter. Use a fine mesh Net or a Pond Vacuum to keep the bottom clean. We have daily pond vacuum rentals available for our local customers who want to periodically give their pond a thorough cleaning without draining their pond completely.

• Add Cold Water Beneficial Bacteria such as Microbe Lift Autumn Prep or Aquascape Cold Water Bacteria. These contain beneficial bacteria and enzymes to break down any remaining leaves, residual sludge and organic matter and sustains biological activity in the cold water through the winter to help maintain good water quality. Maintaining good water quality is the key to keeping your fish healthy until spring.
• Adding Pond Salt is also beneficial to fish. It will stimulate mucous slime coat production, make osmoregulation easier and also reduce the effect of nitrite toxicity. A concentration between 0.1 and 0.25% is ideal (approximately 1 lb to 2 lb of salt per 100 gallons of pond water). The salt concentration can be easily measured using a Koi Medic Salinity Tester. See our ‘Salt in the Pond‘ page for more information .