Hi... Um my family's cat is not eating and he meows very loudly. I should mention that we just got a new puppy and he hasn't taken well to her yet. Is this just stress or something worse?
-- How long has your cat not been eating? Did it start with the arrival of the dog?
-- And is it a complete hunger strike or is he nibbling?
-- How is he reacting to the dog and have they been allowed to interact?
-- How is the dog reacting to the cat?
-- Does the cat have any other symptoms? (ex: lethargy. vomiting, diarrhea, odd behavior, hiding)
-- What's his normal food, wet, dry, brand etc?
Please note that a cat who doesn't eat for 48 hours straight is at risk for a very dangerous liver disease, and in advance of hearing answers to your questions I would recommend you separate the cat and the dog completely until you get the cat eating again.
Agree with Stephen Q. Put another way, if a cat doesn't eat anything for 48 hours, it ceases to matter the cause in the short term: the cat needs to eat or risk liver disease, which can lead to death.
I'd separate the puppy and cat until your cat starts to eat.
And meanwhile perhaps read the hints, instructions in this article.
OK so i'll repeat, you need to separate the dog and the cat and get the cat eating again. Then it has to be a very careful introduction, maybe not even attempted for days from now and i recommend you consult the article referenced in @Ritz's post.