I usually keep feeding bbs until the end of week 4. At this point I start live or frozen daphnia and introduce a small amount nls
grow. Daily removal of uneaten food, poops, and scummys off the tank bottom is good thing with a turkey baster, the bottom-loving fry that are exposed to too much of that bacteria might not develop their ventral fins. Keeping the fry tank floor clean is important at this stage.