Life as we know it................................................. So, now the waters getting cold and your koi are starting to become a little lethargic with the cooler water and that's not a problem, or is it? It normally goes something like this: Water cools off, Koi stop eating, they live on their reserves through the winter, water warms up, immune system compromised due to lack of nourishment, pathogenic bacteria comes on as the water starts to warm, the bacteria is happy cuz' it just entered- The Aeromonas Alley Zone The result= everyone's favorite, Good ole Hole disease. But that's ok because you enjoy catching the koi, knocking it out and then injecting with Antibiotics just so you can save that much treasured Showa, that you saved for the last 6 months for, and that you were planning to enter in a couple months at the next show. However there are no categories for fish with giant healed bald spots. Solution: Be smart, heat the koi, keep it feeding and strong. The immune system will be running at Max and can help defend itself against the ugly bacteria that robs us of the joy of keeping our beloved pets. In the past it hasn't been easy to heat koi ponds, it meant getting plumbers out to run gas lines or propane lines. Now though with the ThermaKoi line of heaters life just got easy for you and more comfortable for your koi. The smallest unit the 1.5 KW unit plugs into a regular 115 volt outlet and the 2 larger sizes, 6 KW and 11 KW are hardwired (230 volt) into the built in junction box that comes with the units.