Every person owning or having the charge, care or control over any dog of the age of four months or over shall pay a license fee as set by resolution of the City Council. The fee amount established for any license applied for where the applicant presents a certificate from a licensed veterinarian that the dog has been spayed or neutered shall be at least 50% less than the license fee established for any unspayed or unneutered dog. A penalty fee, as established by City Council resolution, shall be added to any license fee which is not paid within the time prescribed for payment.