Can dwarf African frogs vomit

I have an African Dwarf frog and sometimes when he is trying to eat he seems to throw up a little. He (oddly enough) eats from the surface, and it might take him a try or two to get to the bloodworms floating above him. Here and there, on some of his misses he throws up a bit of transparent, skin-looking stuff. I think this may be some partially digested food that comes out when he is lunging after new food.