The fish are pretty tough and the cold never seems to bother my fish, but water is too cold for my hands too. Must wear rubber gloves when workin in ice cold water or my hands will be stiff and sore the next day.
Good to have extra air for big koi, I think lack of oxygen is reason most fish die off in winter, and aways the biggest fish will die first when they run low on oxygen. It is simple mathamatics, larger fish need more oxygen and bloody gills are a sign they sucked in too much deadly gases instead. I have seen this with other people's fish over the last 22 years. People forget too that the fish get bigger every summer and the pond stays the same size.
Poor Haro had really bad luck when the power went out and that was most likely the reason they ran out of air. I really feel bad for you Haro, don't give up just yet, hopefully the spring will come soon!!
