Yeast cells are too small for BG yolk fry to eat. Rotifers and cladoceran Crustracea eat yeast sized particles. BG fry first start eating larger algae cells and rotifers for about a week then switch to zooplankton - Cyclopoda and Cladocera.
Don't know if this makes sense, but if rotifers eat yeast cells, and the yolk fry eat rotifers, would it still be good to add yeast to feed the rotifers so they do well, and in turn help the yolk fry?
Much the same concept as I've read on here about grinding up feed to help the fry in your pond, which then feeds the bigger fish.
