I think, for clowns, good flakes foods are better than frozen food. I think if you do a on clown fish breeders , the one that successfully raise clown use dry food for mainly dry food as the primary food.
Several years back, My Onyx was having regular patches of eggs (I only use dry food for my clowns) A friend got the eggs and raised babies. Another of my friend who owns a LFS borrows my clowns to breed them. The first three clutches was great with beautiful babies. Then deformities come for several patches, then the eggs would not hatch at all. The employees only feed the fish various frozen food, several types.
I reviewed their feeding regiments, and told them that the regiment was a poor one for clownfish, but never able to convince them that flake foods are better than frozen food for clowns. I finally took the clowns home and they have continue to produce for me ever since.
Feeding requirement for each species of fish are different, but for clowns, live food and frozen food exclusively, or even as a primary food is not enough for their nutrition.