Three years ago, two crazy Englishmen bought a koi carp on a visit to Hiroshima. The fish has the potential to become the winner of the world's largest and most prestigious koi event, The All Japan Show.
Summer usually means increased pond water loss due to evaporation, which of course leads to topping off our ponds more. You should always add dechlorinator when topping off the water level of a pond. Any amount of chlorine (such as that found in treated water) can be harmful to your fish. Even if it is not enough chlorine to mean immediate death of the fish, this chlorine can still cause harm to proper gill function.