When my puppy first came to my house, he loves to eat and gobbles down everything in his bowl. Now he stayed in my house for one week already but today, he only ate one third of the bowl! Since the last few days he didn't eat much but I didn't gave him a lot of food in his last meal but this is so not my puppy.
Hey there, puppies not eating and consequently losing weight isn't really something you should fool around with, especially if it's been going on for a few days. It could be a viral infection, even if he's vaccinated, or he might just have an upset stomach from eating something other than what you're feeding him. Either way, the best thing to do is probably take him to your vet. Is he lethargic or not wanting to play? Does he have diarrhoea or loose poo? These could be signs of a virus, worms, or an infection from something in the environment. I would say take him to the vet, they can sort out more definitely whats going on, and take the proper action Hope he comes right!