In a previous post I mentioned dying fish. Still losing a fish or two a day. Now I suspect a disease, but what one and how to treat? Fish mouth is open, but not exhibiting breathing motion,just like its mouth is "stuck" open. They lay on the bottom for extended periods and then swim away. My pond shop has been no help and I hate to medicate with the wrong medication. Research on the web does not seem to help except possibly to suggest gill fluke. Our pond is immaculate as far as water chemistry. I have used no chemicals. We did buy four new fish in the spring because a heron had depleted our stock. By the way, the fish are shebunkins. Any suggestions?