They'll eat a lot of protein sources, I typically use tropical fish food for my giganteus (because I spoil them), but you can also use just about any meat you have handy. Just try different stuff and see what they like best. (However, keep in mind meat products mold a whole lot faster than vegetable/fruit matter, so keep an eye on it if it stays in too long).I keep reading Blaberus need protein but what kind of protein? From where? If I'm not using dog/cat food, what am I using? I can't imagine they'd eat nuts. Mine eat mostly romaine lettuce, apples, bananas, baby carrots.