I'll elaborate on FIP from my limited experience: 6 months ago, our one neighborhood stray turned up in yard looking near-dead and breathing very laboredly. Emergency vet pulled a record volume of fluid from his chest. She said sometimes that symptom never returns, and the cause is unknown; other times it returns. Vet analyzed the fluid and confirmed FIP. Cat with relieved chest cavity and subcutaneous fluids still had no interest in anything/felt like crumbs. I consented to the vet's recommendation and they put him down. I suspect all my cats may have been exposed, if it was FIP. They all go outside. Though they've all been vaccinated, my overweight cat has become bony in the last months. (Still obese but bony. Strange combination.) She was vomiting regularly for a while but we thought she was overeating. Pale gums suggest anemia. I'm being vigilant about her parasite preventative. I've been cramming liquid vitamins down her every few days, and they may be helping. She's getting a bit frail. Still eats and drinks. Coat is poorer than usual. No visit to vet yet. Trying to coax her to drink chicken broth, and every little victory seems rewarded. I'm trying to dedicate time to petting her. Attention is the best medicine I may have for her. Her will to live will mean most. All our cats have been free fed for years, so anticipating others may succomb in time if it is FIP. In the interest of collectively holding out hope for an alternative diagnosis, I'll share what happens. When stray was being seen, the vet gave me the impression that well-maintained cats fare better and live longer with a terminal illness like that. I'm interested in getting the best quality of life out of what time we have left. Good luck to all!