They are extremely tiny when first hatched, so insuforia (microscopic) is best at first, put lettuce or grass in a jar or bucket and let it sit for at least a couple of weeks (too late for you unfortunately). BBS (baby brine shrimp), microworms, decapsulated brine shrimp eggs (one of my favorites). The first few days they will survive on their own egg sacks, so that will give you at least a little time to gather other foods. I've never tried it, but some feed egg yolk (hard boiled, tiny bit mixed into water and fed to the fry).
Best of luck to you and your fry!