That is not an accurate article. The fry can live off of the yolk sac for approx. 10-12 days from the time the egg was spawned, depending on the type of clownfish and the nutrition of the brood pair. So if they hatch on day 7-8, like nate said, they have about 3 days to learn how to hunt rots.
I usually feed only one small feeding of newly hatched enriched bbs at day 6-7 and cut back on my rot feeding to once a day. I start otohime A on day 7-8. I find that the one feeding of bbs fattens them up long enough to learn to eat the dry food, but not enough to allow them to gorge on bbs. I would use caution on bbs feedings. This feeding regiment are for my ocellaris fry. They develop faster than percula or some others. They are able to take the size of bbs at day 6-7 where perculas and others may not. I also siphon off remaining bbs the next day because they grow large very fast and IMO lose their nutritional value. If in doubt just skip the bbs.