WinterText Box: Winter If you live in an area where the surface of the pond freezes solid all the way around to where there are no openings, you should put a dried up log in the water. Most any kind of wood is fine as long as it will float, don’t use red wood it is harmful to Koi. The reason I suggest a dried up log is because a dried log will be brown, which will absorb the sun during the day and slowly release the heat it absorbed, during the night, which will create an area around the log that doesn’t freeze, and the fumes and gases can escape through this unfrozen area. This works for me here in zone 5 where some winters are worse than others, sometimes my ponds freeze solid all the way around, and where I need to I use logs from my cottonwood or elm tree, in a few days the sun always defrosts the ice around the log first. So you are thinking you don’t want to put a log in your pond, or maybe you don’t have any trees that you can get a log from, there is another method you can try. Take a one gallon water jug and fill it with hot water to about 3 inches from the top. Then place the jug on top of the ice, you may have to do this several times until the ice melts and the jug is floating on the water. Then remove the jug once there is a hole in the ice and this will provide a place for the gases and fumes to be released and for the fish to get oxygen. Don’t leave the jug in the hole once it is melted through, because it could freeze around the jug and that will cause a bigger problem.