This is my second koi in 4 months who died on me and I’m not sure why. I attached a pic. Bloated body, Popeyes, stop eating, fins look eaten, hiding in the cave. A the rest of the koi seams fine. Water quality perfect, no cold, live in Southern California, 1000gallon pond, 3 feet deep. A lot of oxygen. Please help so I prevent this from happening again.