If you've got the second half of your package with all the critters you can feed them most any meaty food. I've used uncooked cocktail shrimp, silversides, krill, clams, etc.. IME some of the sponges will survive (Orange Ball Sponges, Encrusting Sponges for example) and some won't (most finger sponges). I think the ones that will survive will do so without any intentional feeding and I don't think there's much hope for the others regardless of what you feed them. It's just an educated guess but I'm assuming that the brief exposure to air dooms some of the sponges and not others. The phyto might help for the bivalves, corals, etc.