Hey. I have a tank with a top layer of fluval stratum and a bottom layer of flourite black clay gravel. I put it all in there a while ago because I was trying out the flourite black and then it turned out I needed more substrate. but now I realize that I want to do a better scape and add lava rock underneath for more hight. I'm planning on getting some pigmys and the substrates are bound to be mixed in the process of re-scaping, so I was wondering, will a school of pigmy cories barbels be okay?