Cats can hiss for many different reasons. Sometimes they hiss out of anger and sometimes because of health problems. So it's worth seeing a veterinarian make sure your cat is okay. My cat used to have health problems because I fed him at different times. I work a lot and sometimes come home from work quite late. I decided to buy an automatic cat food dispenser to solve this problem. I found an awesome dispenser on this website 5 Time Release Cat Food Dispensers for Portion Feeding and bought it. I think it's a smart investment.