A pond in winter can be a demanding environment for even the hardiest of fish. Remember that koi are carp, and carp can tolerate a wide range of water temperatures.
Care of Koi, Goldfish & Pond Fish in Cold Winter
Feeding Koi in Winter
Many pond keepers promote the use of wheatgerm fish foods in low temperature conditions but the suggestion remains true… do not feed anything at all if your gold fish or koi are sluggish and the water is very cold.
Koi Food Wheat germ is a great food for use in the autumn months and for those days in winter when the sun shines, conditions are windless, the pond water warms and the fish start to move.
Hopefully during the warm summer months your koi have been fed high protein low ash fish food to prepare them for the oncoming winter. It’s essential to feed your fish the very best high protein low ash koi food you can afford in the warmer months to build up the natural reserves of your koi and other types of pond fish.
Consider buying a suitable pond vacuum to keep the bottom of your pond clear of organic and inorganic debris which looks unsightly and is a breeding ground for anaerobic and pathogenic bacteria.
Winter in a pond can be a demanding environment for even the hardiest of fish, though koi are carp and carp can tolerate a wide range of water temperatures.
These potentially harmful bacteria have a habit of reaching infectious levels once warmer temperatures of pond water are experienced in Spring. It just so happens that this coincides with koi which have withstood a harsh winter not being in the ideal condition to ward off a potentially serious bacterial pond water attack.
Pond Depth and Pond Water Conditions, Stability
One of the big advantages of a deeper pond is that water temperature fluctuations are lower and like many things in nature abrupt changes create problems whereas gradual changes are more normal. This is certainly true in koi pond keeping.
The number of koi keepers (and dedicated pondkeepers and fish keeping enthusiasts) heating their pond is definitely on the increase since easy-to-install, reliable and efficient heating equipment has become available.
In really extreme winter conditions and where shallow koi or goldfish ponds can freeze almost solid many people bring their pond fish indoors to prevent the water from freezing. Even under these circumstances be very careful about feeding fish. Remember koi, goldfish and other types of pond fish can live for very long periods without being fed artificial food.
In fact feeding fish is more for the benefit of the pond keeper perhaps than the koi or goldfish themselves
Serious koi pond keepers (I mean wealthy really) start to check out their boiler systems and get these gas fired or oil fired pond heating systems ready to fire so that water temperatures during winter can be kept around 18 degrees Centigrade.
It’s important to remember that koi are really carp and they do benefit from a lowering of water temperature in winter. In fact one of the precursors to active spawning is the increase of water temperature coinciding with increasing hours of daylight – I almost said sunlight but there is not too much of that in parts of the USA and the UK.
It has been recorded that koi actually benefit from the cold of a winter – just think of Japan, the home of koi-keeping, where temperatures plunge for long periods of time.