I fed my figure 8 on snails and clams and erm... what are they called?... erm... they are like little lobsters... well baby lobsters would do i suppose.
Anyway, i also fed him bloodworms, live mealworms, the occasional deformed baby guppy from my own tanks as well as other deformed baby fishies I might have had in one of my tanks. He liked to use plants to hang and hide in to get some rest. Although they have a rep for being fin biters, mine never did it.
If your puffer is really that tiny little puffer that doesnt get any bigger than say the top part of your thumb then you should have more of the same kind. As far as I know those tiny little puffers are the only kind that school together. But i could be wrong on that account.
Keep in mind that every puffer is different, they truly have personalities. Mine liked to be hand fed, in fact if I didn't hand feed him he would hardly eat. And from what I have seen from my own puffer, they can get attached to their human. When my husband walked in while I was feeding my puffer would hide. As soon as he left the room my puffer would come back out and feed again. But like i said, every puffer has a very distinct personality. Just sit there, watch yours and bond with it. Most puffers are in my experience like miniature underwater dogs...lol