Prepare Your Pond For Winter

Koi Ponds and Water Gardens

If you live in a region that has freezing temperatures for extended periods of time, it’s important to prepare your pond for winter well before the ice comes. When the summer temperatures begin to cool and the leaves start to turn color, it is time to take your first steps.

  • Use Pond Netting to cover your pond and prevent it from filling in with leaves and other debris.
  • Do a partial pond cleanup so that you do not have too much organic debris decomposing in the pond over the winter. We do not recommend a complete pond draining and cleaning unless things have really gotten out of control, because this sort of procedure is very stressful to your fish, and will harm your pond’s beneficial bacteria population. Ideally, you should clean up the pond before the water temperatures get too cold so that the fish have a couple good weeks to feed and recover from the stress of the pond cleaning. Pond Vacuums, Nets and other Equipment are available on our website to help you with the project.
  • Feed your Koi a Wheatgerm-based diet and reduce feedings to once a day with water temperatures in the 60’s F and once or twice a week with water temperatures in the 50’s F. Good diets to use during this period are Keystone Koi Pellets, Blackwater Cool Season, and Tetra Spring & Fall Diet. Be sure to use a Pond Thermometer to monitor changes in water temperatures.
  • Set up a Winter Aeration System to keep oxygen in the water and help dissipate toxic gases. We believe it is important to aerate off to the side instead of in the deepest water, because overly vigorous aeration can make the water too cold for Koi to safely overwinter. Some people choose to use a Floating Heater-De-icer instead, and others put both in so that if one fails, the other will save the day.
  • Create hiding spots for your fish at the bottom of the pond. Fish like to go to the bottom of the pond and huddle up underneath something and wait for warmer days. Some people make caves or tunnels with tubing or flat rocks, and others use plastic culvert pipe, or like material.
  • Don’t turn off your water pump until the night-time temperatures are dropping below freezing. When this happens, pull your pump and put it inside for safe keeping, clean all your filter pads and remove your Bio-Media from your water filter and put it in a Mesh Bag in the bottom of your pond for winter. By doing so, when you start up in the spring your Bio-Media will be alive and you will have instant filtration, avoiding the dreaded “green water phase” of start-up.

Natural Ponds and Lakes

The size and very nature of these water bodies make them impossible to micro-manage like you would with a Koi Pond. However, there are definitely things you can do to get through winter in better shape.

  • A Winter Aeration System is very important for almost any pond that freezes over for a significant period of time. Snow on top of the ice prevents sunlight from reaching vegetation, and as a result, the vegetation uses oxygen instead of giving it off. This can quickly lead to oxygen depletion and fish kills. A properly sized and installed aeration system will prevent this by creating a “breathing hole” for the pond. Be sure to aerate off to the side in 50% of the maximum depth during the winter to prevent super-chilling the water, which can kill fish.
  • Use an Aquatic Rake to pull excess weeds and leaves from the water before winter. Weeds under ice and snow use up oxygen and decaying leaves cause poor water quality, so get them out if you can!
  • Fall is a great time to stock Minnow and Gamefish because some species are only available in the fall, and minnow stockings put some extra meat on the bones of predator fish, helping them get through the winter. Email us at if you are interested in stocking fish.