There has been publications on expressing HRP in zebrafish neuromasts and by DAB staining do correlative fluorescent and electron microscopy. I have tried to repeat the same technique for cells that are deeper in the tissue. I can get DAB staining by using detergents but then cell membranes look very disrupted. I'm looking for a way to preserve cell membranes and at the same time permeabilize them to DAB.

I'm not sure if I got what you mean by cryostate!

in case of perfusion, I tried to make holes in the embryo while they were in the DAB solution, it didn't work for fixed embryos and although it works for unfixed embryos but tissues start dissociating and doesn't give good results in EM.