it's true, i have fluorite and i'm trying out some options before i replace all my substrate. 3 out of 12 of my cories have some ragged barbels and are acting weird. there was no problem until i moved everyone into one big 75 gallon tank and replaced my regular gravel (which was just rounded little pebbles) with the fluorite gravel. so, in addition to adding another mini- gravel vac mid week i'm trying to add some surface options!!
maybe i'll try making a little sand pit area in a terracotta water dish and see if they all hang out there. thanks everyone!