Hi,
Heh heh yeah - I now have to be very carefull when opening the tubs on feeding day.
I'd probably recommend waiting until the next scheduled feeding day - offering too often can stress some of them out and actually reduce the chances of them eating.
I'd probably examine him to see if there were any odd signs inside his mouth or noises from his breathing.
How closely are you matching the way he was fed at the previous owners?
dr del