| Kusuma: I'll venture a guess, but that is all it is: If your tank is above ground, the water temperature will be approximating the air temperature of 30C. (For the conversion-impaired, 30C is about 86F.) If the sun is shining on the tank during the afternoon, the water temperature could be rising well above 33C (over 92F). These would be very high temperatures for koi. Additionally, if you are having frequent rain storms, there will be dramatic fluctuations in temperatures. Consider that these fish were likely imported from Japan recently and kept in shaded in-ground ponds. In Japan the water temperatures were likely in the 20-22C range, or a bit lower. Your dealer probably was not above 23-24C. After the stress of shipment and being in a dealer's inventory, they have gone to another stressful situation at another extreme of their endurance range. The loss of Hi has been observed as coinciding with stressed conditions. If you can find a way to cool the water and keep the temperature stable, you may find there is improvement. ...Like I said, this is a guess. |