I extend my condolences. I can only imagine how frustrating this must be. Sorry for your struggles and losses.
Sorry to hear about the beagle. My old cat went downhill in no time with malignant tumor and kindney infection and didn't even need to be put down as he died within days. Even a vet couldn't help him, so I wonder how many fish die just like that too, which is impossible to diagnose in most cases for the peace of mind if I may say.