Is the idea that you want to create a fine particle suspension that will settle onto the bottom of a container creating a film of particles which you see the movement of snails?
Do you have a blender? You could blend the food in water. Then let the particles settle for some time & pour off (decant) the fine particles that didn’t settle. Finally resuspend the particles in the volume you need.
If you don’t have a blender available you could grind the dry particles with a mortar & pestle (kitchen or lab) or perhaps in a coffee bean grinder (just don’t tell the coffee drinkers what you have done!
