I personally like crickets the best. just make sure that they are no bigger than the space between their eyes. When I first got my beardie, I was really bad at getting the crickets from their container to the calcium bag without loosing some, and we would find them in random places in the apartment, but they never reproduced in the apartment, they were just crickets that got loose... lol They only live for 6 weeks, so It's not so bad... It is a real pain if a cherping one gets loose, and you know it's somewhere in the bedroom, but can't quite figure out where... that's no fun... 7 inches is still pretty little, I would stick with crickets for a couple months, you can get really, really small meal worms for them (I did and it was fine) but I've heard that it's not the best to give to young beardies, but you can get them pretty small and I've never had a problem with it. You can get phoenix worms (you probably want small sized phoenix worms). I didn't even know what those were when Puff was young, but if they're small enough, i'd say go for it...