Winter Care. The Golden Rules

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1. DO NOT switch off pumps and filters. wp1.jpg (30670 bytes)

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Your filtration system will not work as efficiently during the colder winter months, as the friendly bacteria in your filter will die off to some degree and will not reproduce so readily. However, you fish are still producing ammonia and it is vital that your filtration system is still functioning to keep your water quality in an ideal condition
2. Turn off water falls if present. Your Koi need a Stable environment In winter, your waterfall will act like a large radiator and cool your water very quickly to the same level as the ambient air temperature. So switch it off if possible.  Similarly, you should switch off venturis if possible to avoid your water being cooled by the air flow through the venturi.

Cold water is capable of holding far more dissolved oxygen than warm water and extra aeration at this time of year is not required.


Your koi will appreciate a stable environment. They can withstand a broad range of temperatures, pH levels, and even pollutant levels if stable.  They DO NOT like rapid changes in temperature or pH especially. If you have a small, shallow pond, these parameters are more likely to fluctuate quickly. Larger, deeper ponds provide a better, more stable environment for your koi, specially during the winter months.

3. Reduce feeding. wp.jpg (16165 bytes)

If you own a small, shallow pond, water temperatures will fluctuate more quickly during winter. On a mild day in winter, your koi may be looking for food. Should there be a sharp frost overnight, temperatures will fall quickly.   If you have a smallish pond, DON'T feed when the  temperature is 50 deg F or less.  If you have a pond of sufficient gallonage and depth, you can feed down to around 46 deg F, since your water temperatures will not fluctuate substantially over a short period.

Your koi are poikilothermic, that is their metabolism is governed by the temperature of the surrounding water. As the water cools, they will become less active and seek less food. Their digestive system will be less capable of processing food at lower temperatures, and food will stay in the gut longer. Too long and you are in trouble!   Feed low protein or wheatgerm food during the winter providing your koi are looking for food.  Generally you can feed at temperatures down to around 45 deg F.  However, if you have a small pond which may be subject to rapid temperature fluctuations, be careful not to feed if there is  a chance that the temperature could drop very quickly overnight.
4. Provide adequate protection. Koi can stand low temperatures with little problem, but if temperatures remain too low for too long, problems will occur. In Britain (depending on where you live) pond temperatures can drop below 50 deg F during September and stay below this level until May the following spring. This scenario would almost definitely cause your koi problems. To improve this situation, and 'shorten' the winter, you can provide heating for your pond, via electric or gas heaters, or you can protect your pond from the effects of wind chill by covering the surface with bubble wrap or some kind of giant cold frame to keep out the worst of the weather. Even a simple measure such as applying bubble wrap can increase your water temperature by up to 5 deg F If you decide to use a bubble wrap cover for your pond to retain warmth over winter, ensure that you leave a portion of the pond uncovered in order that noxious gases can escape easily. Ammonia,   hydrogen sulphide and probably methane will be present, even during the cooler months. If these gases get trapped under your cover, they will redissolve in the water and cause BIG problems before spring arrives.
5. Prepare













shiro.jpg (16766 bytes) Get ready for winter!

Ensure that you clean filters and hoover your pond floor BEFORE winter sets in. Check pipework, pumps, filters, electrics, air pumps to ensure that they are all in good condition and working properly BEFORE winter arrives.

Treat any sick fish while water is warm to improve their condition as much as possible so that they are as well prepared for winter as they can be.