Hmmm need more water changes. Need weekly water changes . Not sure why you got idea not to feed hiM daily. Don't afraid feed him daily. I feed all my bettas daily and they are old. Do not forget to swish/rinse the filter media to rinse all that gunk off that it gathers daily from the water. Water parameters checking for the ammonia but not show you other contaminants. So your really need to clean the filter and do more water changes. And i would love to see the pictures. Post them in your last thread so we can see them.