Although, it is not cold in south-west Florida right now, the night temperatures are in the 60s F (15 C). During November, the water temperature in my ranchu pond fluctuated between 59-72 F (15-22 C). Pumped out of the ground well water is at 75-76 F (24 C) and comes much warmer than the water in the pond. The challenge becomes greater to perform water change, as the water in the pond is colder.
This temperature difference can have a negative effect on ranchu if exposed suddenly. Floating tubs with ranchu in the pond, brings the two temperatures closer together very quickly. As soon as the difference becomes less than 3 degrees F, the fish are good to go in the warmer water. Temperatures can be instantly checked with
IR thermometer.
