Of course it's impossible to tell what yours are up to, so all I can really offer, is to tell you what I do to transition fry.
As soon as the fry are free swimming, I start feeding newly hatched artemia that have just been hatched in either plastic hatcheries inside, or outside in small ponds, and if I have them in spring and summer, newly hatched daphnia. After a day or 2, I start to mix in pureed flake, or pellet dust soaked in tank water with a turkey baster of pipette, and shoot it in with the cloud of artemia and into the school of fry, this seems to help the fry associate the "dead"/inert stuff with the moving artemia.
I like to have at least 2 artemia hatcheries going simultaneously , each started a day apart. I usually start then a day after the fry become wrigglers, this gives the artemia eggs 24 hours to hatch.
I may also blend in thawed peas with the flake.
I hatch them outside in just about anything that holds water in summer.
and after harvesting the newly hatched, the old water and unhatched eggs are dumped outside, where some eventually grow into adulated for larger fry and fish.
