Ive never had glofish, but Ive kept danios. So its not like they are completely different. Danios are one of the most hardy aquarium fish.
They would get along, but you need at least 20 gallons for these fish because they are a very active schooling fish. So if you buy them, you need at least 6. Because they school. If you dont buy a small school of them, Danios are known to be fin nippers. So the danios would actually harass the guppies if there isnt enough of their own species to harass and keep them entertained.