How is your puffer doing?
Some times it takes fish longer to adjust to their new surroundings. I know when I have a new addition I do not let any one except me around the tank for a week or two depending on the fish. Puffers can rest on the bottom, mine rested on the bottom just about all day yesterday and only came out for the night feeding.
Avoid any FW
feeders at this point, you can try Ghost shrimp but feed the ghost shrimp something nutritional first before placing them in your tank. Get a feeding stick from your LFS
(about $1.50) place a piece of Fresh raw shrimp on the feeder stick and see if the puffer will take it. You can also place the raw shrimp in a nori clip. This will help avoid excess uneaten foods in your tank and your puffer may be less stressed during feeding.
When moving a puffer, scoop the puffer with a plastic cup, pitcher or bucket, try not to expose your puffer to air. You can put snails, hermits or even mussels from your local grocery store for the puffer to eat, this will help keep the teeth down. But offer a variety of foods, Mysis, Mussels, Crab, Squid, Raw Shrimp and so on.......