When the temperature of your pond nears 50 degrees it is time to decrease the feeding of your fish. You should feed only once per day, and only feed about 1/3 of the amount that you normally feed. Your babies will beg for more, but ignore them for their own sake. Within a couple of days they will adjust to the reduction in food and beg less. When the water temperature hovers around 45 degrees it is time to stop feeding the fish all together. Many of you have told me that you feed your fish all winter and have never had a problem, and that may be so, but winter feeding can be dangerous for your fish. In winter your fish are in somewhat a state of hibernation. Sure they swim around and graze on the algae, but as a result of their body temperature being so low, their immune systems are at their lowest and their digestive tracts are only suited to digesting very fine filamentuous algae and the occasional bug or two. If you will look on your food containers, you will see that the protein levels in most foods are between 35% to 47%. The hibernating fish's digestive system simply cannot digest and make use of the extra protein. Consequently, this can often lead to a condition called sepsis, where bacteria enter a weakened fishes body through wounds or the fishes digestive system. In either event, the bacteria can cause the failure of the internal organs, and can result in symptoms that you might recognize as clamped fins, red bellies, reddened eroding fins, etc. See Dr. Johnson's book, Koi Health and Disease page 56. If you absolutely cannot resist feeding your fish something at least once in a while during the winter, try something very lite like one or two crushed Cherios. Just don't assume that it is ok to feed your fish Cherios all the time. Because it is not. That is a whole other dietary matter that we will not cover at this time. Buy yourself a thermometer for your pond. You can get them at any pet store for as cheap as $2.

Boy, this is like writing a book. Not a bad idea! Now we will move on to pumps and waterfalls. Do you, or do you not run your pumps, falls, and filters all winter? Well, this is the million dollar question that we are going to reduce to about $2.95. First of all, most books will tell you that the water in your pond in the winter will stratify, which means that there are different temperatures in your pond at different depths. Today I will tell you that it is just not so, if your pond is less than 36" deep. Even if your pumps are off, your fish will still swim around in the pond, and as they swim they stir up the water, and any water that might be fabled to be stratified will be just about as stirred up as it ever was. Besides even if there were a temperature difference between the top water and the bottom water, it would be only about 1 to 2 degrees in less than 36" of water. It is a fishes natural reaction to go deep when the water temperatures cool, and I have actually had fish to lay on their side on bone chilling days, as if they were dead, all the time trying to get closer to the bottom. If you want to run your pump and filter all winter long there are a few things to consider. If your pump supplies water to a waterfall, the water will go through evaporative cooling as it passes over the waterfall, thus reducing the temperature even cooler than the outside temperature. You can see for yourself the effect of evaporative cooling by licking the back of your hand and blowing on it. As the moisture evaporates, your skin is cooled. Unless your fish have a wet suit, don't run your waterfall in winter. (I wonder how many people around the world are simultaneously licking their hand. You know you tried it!) If you want to run your pump and filter all winter, rearrange some piping and allow the water to re-enter the pond below the water level if you have an external filter. If you have an in the pond filter, disconnect the waterfall line from the pump and let the water simply recirculate in the pond. On the very coldest days when things tend to freeze over, you may want to shut your pump off entirely. Another alternative is to purchase a sinking pond deicer/heater. They have a built in thermostat that turns the unit on when the water temperature drops below 40 degrees. You simply drop them in your pond on the coldest days and plug them in. They come with a protective shield so that they can be used in ponds with rubber and vinyl liners with no risk of damage to the liner. They run about $49.00. If you use a UV Sterilizer on your pond , you should winterize it so that you do not break the quartz sleeve and bulb if water freezes in the pipes. Be prepared for winter. It's a snap!

Helpful Hint:

If your pond freezes over, never hit or kick the ice to break it up. The impact can give the fish a concussion. If you must break up the ice, either full a pot with hot water and sit it on the ice to melt a hole. Or if the ice is thin enough, simply gently press down on the ice and break it, after which you can lift the large pieces out of the water and discard, leaving the surface somewhat clear. Fish will suffer little harm from ponds that freeze over for short periods of time. Frozen ponds only become a problem after their surface is frozen solid for more than a few days. Fish continue to respire underneath the ice of a frozen pond, and the carbon dioxide continues to build up and cannot be degassed through the waters surface. This condition is known as Carbolism. Humans can suffer a similar fate in a tightly closed room over a period of time.

I hope that you have found this article helpful.

Greg Crane