Winter is almost coming, and this will be the first time for your pond to experience cold weather. Wintertime is a downtime for your pond, because during this season, there will be lesser events compared to other seasons. In order to make sure that your Koi and your pond will survive the weather, here are the necessary things you need to take before winter comes.

First, clean up - Take your time in completely going over your pond (this can take about a weekend). Remove those unwanted bulk material inside and around it as well. Inside the pond, remove all of those materials such as leaves and slits from the bottom of it. If you have flowers or plants that wouldn't survive the cold weather, remove them as well.

Around your pond, clean up those things that can be blown into it, because you won't be able to notice those debris until the end of the winter (this will then prevent those potentially harmful parasites and bacteria in the future).

Second, stop feeding - Keep in mind that your fish needs to stop feeding during the winter period. Feed them only once per day when the fall begins and temperatures will fall around 55 to 60 degrees Fahrenheit. Completely stop the feeding once the temperature hits below the 50-degree mark (even though the temperature will go beyond this mark, you should refrain from feeding your pets).
Most of them take at least 4 days for them to digest food completely when they're healthy and temperature is above the 50-degree mark.

If you will forget this important step, you'd end up killing your fish! Don't mistake it for hunger when your fish open their mouths to you, as it is only a learned reflex rather than a sign of hunger. Don't worry about not feeding, because your fish will feed on something else besides the food that you provide them (especially if your pond has a great amount of natural plants). If you're not feeding them and if ever they get hungry, they will feed on this.

Third, check up - Do a seasonal check up on the equipments that you have, from your filtration system to your array of preventable medications. Remember that most of the ponds lie dormant during the winter, you would be able to have lesser chances of finding the stuff you are going to need. Ensure that your emergency kit (including the nets, medications, bags, and water testing kits) is always ready and up to date.

Fourth, prepare for the cold - Make a preparation for the cold weather by investing in the items that you'd be needing during the summer time. The Koi can withstand constant temperatures falling as low as 39 degrees Fahrenheit for minimal amounts of time (which include those that fall a little bit lower than 39 degrees Fahrenheit).

If you buy a heater, do a research first on the size that you'll be needing in order to heat your pond during the winter rightly. Otherwise, ice will still form, causing harm brought about by the amount of gas in the water, as it is trapped under the ice. In extreme cases, you can also put inside your pond an emergency tank.

Finally, turn off all of your water sources - Your heater will do its work harder in order to maintain the temperature suitable for your fish to live in the cold weather. If you have those add-ons like streams, waterfalls and fountains, you should turn them off during the winter (as they will circulate water and constanly bring new and cold water to your Koi pond). By switching them off, you will make the standing water in your pond the only water the your heater will be working on.