The fry eat Baby brine shrimp, which aren't sold hatched. You have to create or buy a hatchery and hatch them yourself.
Good luck with your fry. I really hope they survive. Living fry are a lot more time consuming than the research required to get you experienced an knowledgable enough for breeding. I would seriously consider doing a lot of research over the next few days, or your fry do not stand a chance against you. Not trying to be harsh, but unfortunately, that is the way it is.