When free swimming micro worms. After a few days I continue microworms and add a few bbs newly hatched. After 1 week it is mostly bbs and a few microworms for the late starters. I always add the microworms first as it helps even the larger fry to have a varied diet. At about 3 weeks it is mostly bbs. Today at three weeks I gave them a pinch of finely ground flake food. I did see some of them testing it. If they eat some it is vitamin enriched!
You can see which ones are eating the bbs as they get huge pink bellies.