So recently I had a episode with my fish. In which the larger of my two shubunkins was lethargic, lost her appetite and was surface breathing. I treated with aquarium salt and aquarium coops paracleanse prophylactic dosage suggestion. However during the treatment I became more suspicious that the issue was more related to long term exposure to small amounts of copper and chloramine I wasn't aware of in the water. I fixed all water issues but now about a month later the fish exhibited flashing behavior the other day and the largest of the two started surface breathing and acting lethargic again. I turned up the aerator, which is rated for a much larger 500 gallon pond, and the surface breathing stopped. It's been two days since this strange behavior. I've seen some darting behavior since but no obvious rubbing that I can positively identity as flashing. Obviously there's a problem with oxygenation but I am having a had time identifying what is causing it? Parasites possibly. It makes no since that the dissolved oxygen level would be low. Its a 125 gallon pond, the aerator is rated for a 500 gallon pond and it wasn't even turned down to half. Plus there is a waterfall that runs 12hrs a day in addition. I see no signs of ick but their Shubunkins the speckled pattern makes it hard to be certain. It could be gill and fluke and my dosed down treatment only knocked them back periodically. I would just watch and wait but I am really concerned about the weather changing and being able to safely reacclamate them back out into the pond. The water is down to 65.5 F already. Help I need advise from those more experienced!