Water parameters should be checked at least once a week
through the winter months.
A lot of people tend to "let it go" at this time of year.
Koi are cold blooded animals and their metabolisms are slowed down through
the winter. But, they still produce ammonia --- just at a slower rate.
Water is heaviest at 36* F. You can have 38*
water on the surface and you can have 34* water (or ice) on the
surface. When this becomes important is if you're pumping water from
the bottom of the pond if the water on the bottom is warmer than the water
above it. You're cooling down the koi's comfort area in the
pond. If you're going to pump water for whatever reason through the
winter, you should pull it from 8 to 12 inches below the surface and return
at or below the water surface.
If you have a sufficient snow load on top of the ice it
will block the sunlight. This will cause the algae to either use oxygen and produce carbon dioxide
(all plants do this at night) or die ---
creating an ammonia problem. Either way it's not a good thing.
You should remove enough excess snow to allow sunlight into the pond.
Water sprayed from the garden hose does this pretty well.
Koi DO have teeth. They're in the back of their throat and used for
grinding. They lose them occasionally as they're replaced with new ones.
These were scavenged from the filter through the summer.
Salt water is heavier than fresh water. It can form layers of different
densities in your pond if there isn't enough mixing. NOT a likely
occurrence, but it can happen. When testing the
salt level, it's a good idea to pull a sample from the bottom as well as the
top to confirm proper mixing has occurred. This is more likely to
occur in a wintertime scenario where the water is being pulled from just
below the surface and there aren't large enough fish to sufficiently agitate