any suggestions on making food sink in a pinch?

due to whatever mysterious illness is afflicting my fish, my firemouth is unable to get himself any higher then an inch or two off the gravel and doesn't seem to be getting to the floating food. he picks through the gravel come feeding time but, while i'd like to keep him plump in case he pulls through whatever it is he has, he's beginning to look quite emaciated and i can't for the life of me find a place in the city that sells sinking pellets besides the algae wafers. he has been picking at those when i drop them for the corys and cats, but really they aren't exactly cichlid grade nutrition . i was wondering if anyone has any suggestions for possibly rigging up a sinking feeder i could use to hold down the floating pellets, or perhaps if there is anyway to either make floating foodstuffs sink or cook up something that will.