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.
Jeff.