I have a very similar situation with my clawed frog. She is in a 55 gallon tank with a buddy and some larger fish. She suddenly stopped eating and hangs out at the top of the tank all the time. I hear her made audible noises that sound like a duck quacking. It's been over a week now that she hasn't eaten anything. She just pushes food away when I try to feed her. The other frog in the tank is totally fine and has her normal hearty appetite. I had my water tested and all was well except for a low pH and alkalinity. I purchased Marineland Easy Care water treatment and did a 25% water change. I'm getting worried that she is going to starve to death. I'm not sure what to do with her. Any thoughts?