Yes, I use Repashy Soylent Green for my hillstream loaches (including fry!) & other auf wuchs grazers. Alan Repashy also sells other food formulas for fish & reptiles, I tried the shrimp food but none of his others. I like that it can last 24+ hours in the tank so there's always food available for my fish. It's just learning how much to feed to last that long but not much more. I mix up a bunch & freeze it. Then just thaw enough for a few days.
I know I've used First Bites a couple times but can't recall what fry I used it for...a long time ago.
Flake is easy to feed, but also easy to overfeed. Water changes & vacuum! Again, WCs & variety! You & your fry are doing well, keep it up!