The pond has kept the ranchu at a steady temperature of around 15 degrees C.
The ranchu are all looking really well and even in the cooler water, they are still very active. I have observed that recent conditions in the ponds appear to have resulted in increased wen growth on all ranchu.
There are many factors to consider, but it is the first time that i have seen obvious wen growth across the whole group at the same time. I guess with all the ranchu nearing Oya age, and perhaps maturity, natural development may become less extreme and changes through grooming become more obvious.
I will now begin the slow process if reducing the pond temperature for the wintering that the ranchu will endure. The cool down will take at least a month and so by starting now, the ranchu should be at the winter temperature by mid/end november. I will hope to keep them at 6 degrees C until at least late Jan, when i will start warming them very slowly once again.