Sitting in our fourth big snow storm in Pennsylvania in an unseasonably cold and snowy year I thought I would share my experience on winter Koi keeping.
When it comes to dealing with nature my approach is always back to nature because I figure she knows whats she is doing with about a couple million years on her resume. Koi have no issue with mild snow/ice as they are from seasonal regions, that being said… all snows/winters are not equal. Because we were hit with snow storm after storm my ponds have been covered in snow and that bad in nature observing opinion. Looking at natural ponds and river systems they thaw quicker then small garden ponds and tend to have air holes(at water entry pond from warmer spring or stream inlets), thus this is the what we should replicate. I can guess light and aeration are among the reasons why but will not claim to know all the billions of bacteria supporting pond life nor the inputs their systems need to replicate natures balance.
I always clear off the snow from my ponds if the snow doesn’t melt after a few days to allow the sunlight to penetrate the ice to reach the bottom of the pond. Most problems with Koi tend to happen in the early spring because the unnatural ponds we have are out of whack and there is no balance allowing a parasite, bacteria or algae to thrive beyond what it could in a natural balanced pond. A big part of this is letting the pond stay in darkness too long.
I also like to turn off my falls and stream in the winter and relocate the pumps from the deep to the shelves as to not chill the water too much. For aeration I rig up and little angled PVC that only an inch or 2 above the surface reducing the chilling affect but keeping the spec’d pumps max aeration. If your like me, I don’t always get every leaf out of the pond from fall so I ensure I don’t run into problems from leaves from breaking down with the max aeration. This PVC will freeze over in the coldest times but comes right back to action as soon as the day ventures over freezing. Oddly I have never lost a pump this way so i never used an idea I have including a pressure relief valve to a second underwater pvc to kick in when the above water line freezes. Lastly this setup keeps an air hole always open for the Koi without me having to drill one, fall in or rip the liner banging open one(yes i’ve fallen in up to my knee in winter, shame I was dumb enough to but thank goodness I became smart enough to stop) or run a surface deicer.
I use 2 1 inch PVC elbo’s and no more then 8 inches of PVC works well and only freezes when it get down to the teens. I would not recommend this for a pond less then 3 feet deep, in that case use a good pond heater.
I’ll leave you good folks with an awesome sub ice Koi video from Davids Cooks youtube. Great video David!