Kendra
That sounds like a pretty good diet for him. You might be feeding him too many dandelions, I give my guinea pigs 3 leaves each but I also offer tons of other different kinds of foods like grass, romaine lettuce, cilantro and parsley... they also like tomatoes :) oh and green peppers are very very good for guinea pigs, they are high in vitamin c! make sure you feed him timothy hay when he gets older and stops growing, because alfalfa is high in calcium (which guineas need when they are younger) but when they are older they can cause bladder stones. Here is a link that may help you out :)