Winter water changes

[RKM]

The ice has melted over my pond (in CT) and therfore I was wondering whether I should take advantage of the opportunity and do a partial water change. Would this be advisable?

[James P]

RKM, This is a tough one to answer as it really depends on- what condition the fish are in, how much rain has gotten into the pond, what the pond's total volume is and how stable the pH is. This is all important as a water change could be a refreshing thing or a disruption to an already stressing situation.
You are not far from me and this year we have had an extraordinary amount of cold rain. If your pond was covered and/or frozen, the fish were spared the shock of temperature and pH shifting. If that rain got into the water and your overall volume is less than say, 5000 gallons, then those fish are likely very stressed. This gets even more 'iffy' if the koi are small or have only been in this pond for a short while ( just this summer for instance) as they have not acclimated to your conditions ( that could take an entire seasonal cycle).
Sorry I don't have a simple answer but its a complicated dynamic with loads of variables. Maybe if you supplied more information? Is the koi pond 'running' by the way? Is the water circulating? JR

[RKM]

The pond is ~1000 gallons, with 5 fish in it (3 ~12" and 2 ~8"). I shut down the filter when the water termp reached 45°F. It has received a fair amount of rain over the last month, with more expected over the next few days. I confess to not knowing the pH, etc. at the moment. However, the fish do not show any overt signs of stress (which probably means nothing).

[James P]

Well, I'm sorry but that is not a promising beginning to what is looking like a long winter in this part of the country. 1,000 gallons is kinda of small when you consider the amount of water that will flow into it from the rain and snow. If the pond is shallow ( really ponds in our area need to be 48 inches minimum), the dilution effect will be powerful.
When koi slow down and attempt to survive the challenges of winter, the key to success is stability- of pH, Temperature, oxygen levels and low organic and inorganic toxins.
You fish are also young. Meaning they have limited body mass to endure a LONG winter.
I would study the tent cover that is posted in another thread here on KB. Try and get it erected in the next week over your pond. If you can get that done, I would do a small water change of no more than 15%. Try not to disturb the koi as every movement spends stored energy.
With a tent in place, you might explore the possibility of restarting the filter system ( depending on the type and its location). Don't feed and keep on eye on them.
We tend to have a winter frost in early Febuary. If this happens this year, you can be ready with an indoor facility in case the koi look red and stressed at that time. Best of luck. JR

[Regenmeneer]

JR,

I was just wondering if you would consider a continual, very slow water change an option in this case? (Of course a overflow system must be in use in this case)

Regenmeneer

[James P]

very small amounts of good quality source water can be used and can even add heat to the pond water. RKM is about three hours away from me so I know what his winter is like. It is not unusual for the air temps to get down to 9 - 18 F for 10 day stretches in January. The wind chill can bring it lower- much lower. Our frost line tends to be 30-36 inches minimum. So he can't count on the earth to add heat. So I some warmer well water might be a good idea. But only if he tents the pond to keep out the rain and sleet we get. Otherwise, and quite ironically, the fish might be better under the ice as the lesser of two evils. And obviously, city water is loaded with chlorine and chloramines so this would not work in 1000 gallons on a continuous basis.

JR

[RKM]

My water is from a well, which I am having analyzed as we speak. Tomorrow I'll go to Home Depot and pick up boards and plastic and build a cover for the pond. Since I have a deck right next to it I can build a lean-to cover for it, which will allow the water to run off more readily (and snow can be brushed off more easily). I'll do my best to fully enclose the pond with the plastic.

[MikeM]

There are a lot of people in RKM's situation. I wish more were aware of this type of advice.