If you think your cat might have pneumonia, you need to take him/her to the Vet. This can be very serious and would presumably require antibiotics. Additionally, even if it isn't pneumonia, if he has a fever lasting for more than 24 hours, OR if it's higher than 104 degrees F he should see a Vet.Can anyone help me with cat fever ? My 3.5month is feeling under the weather had fever n now eats very little. I am scared of pneumonia as it is pretty cold here.