Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
Did you mean to say the whitefish was rotten or was that typo?
Any retching, gagging, lip licking, drooling, vomiting, or diarrhea?
Is still taking formula and having as much as she should? Is it puppy specific?
Can she move her back legs? Does she just seem weak?
Are her gums nice and pink (not white/pale)? Moist or sticky?
If you press on her belly, does she have any tensing, tenderness, discomfort, or pain?
Could she have eaten anything she should not have (ie bones, toys, plants, chemicals, human meds, etc)?