If anybody could quickly help me out, that would be great. I just changed my water in my koi pond, and now one of my two koi is floating on its side at the top. It can sometimes flip itself back over, but it keeps on going to one side; when I personally go and flip it over with my hand, it swims to the bottom. My fish usually stay at the bottom of the pond after a water change, but I'm not sure why one of them is flipping over this time. Maybe the water is too cold? I'm not too sure; I got these koi about four months ago (about a year old), and there haven't been any problems until now. Thank you!