I have one of those..two heads on a frag plug. Right now I have it at the bottom of the tank with a decent water flow under CFs but am getting ready to move it to a Nanocube with an LED
setup. Your description should help with the new placement and extra care and hopefully get it to grow
..the heads look larger than when I got it but it is still just a pair.
Which Rod's Food are you using and which suppplements? I do dose with B-Ionic after each water change, once a week, and someone else put me onto Rod's Food Herbivore for my Blenny.