A coffee grinder sounds like a great idea! I've tried smashing AM with a hammer in a plastic bag and a food chopper. I wasn't happy with either of my methods, that food is really hard.
What I didn't like about making the food smaller is that it no longer floats. I bought some tropical fish flake food (Tetra Min) to feed the smallest minnow babies. They loved it and it floats so I could still watch them eat. I only feed occasionally so a small jar goes a long way. The hydrated food works well too but my baby minnows seemed to prefer the Tetra Min.
The benefit of a burr grinder over a blender or blade grinder is the ability to control the size of the product. You'll still get some fine dust, but the burr gap will determine the size of the largest pieces. I had to work with the set up of the grinder to increase the gap because I wanted chunks much bigger than a coarse coffee grind. Now I get nice fractured particles all the way down to dust, so there's food pieces sized for everyone.
-RFL
