I have also had some luck crushing pellets into very fine crumbs, almost dust, I try to introduce it to my fry from around 8-10 weeks initially they will eat it when its in the water column but not off the bottom so use it sparingly when you first do it as you will need to siphon out any excess.
As others have said I'd still continue with BBS for most feeds, the crushed pallets is just a way to mix up their diet and not be so dependent on the BBS
Try mixing BBS with dry food. Over a month slowly reduce the quantity of BBS. I found the only dry food that my apistos take eagerly is Bug Bites pellets. Have you tried this product? You will need to grind it finer for fry.
When feeding young fry frozen [when out of BBS] food I take it frozen and grind it through a strainer first than a fine wire mesh strainer and if really small fry then through pantyhose, and like Mike said with dry food for about a month.