I have a geophagus and a heckelli...not the exact same fish but same genus... Nice fish, I keep them with other south americans, check signature for list...slow growth rate for me, and yet they are very well fed.
Not a big eater, will take what he needs then ignore the rest. Has shown agressivity with my green terror lately, the heckelli is large and wild caught so could make the difference for agressivity. Good looking fish, they both grow trails at the tip of their fin and tail. If you want pics I can post some...
What Geophagus do you keep Cyclop?
I am keeping heckelii too, and that one is eating from my hand. It do not dig too much either, only a bit when it is food time. But it don't dig up plants.
I searched some about the gymnogeophagus and found this site. Maybe you'll find some info there. It looks like an awesome cichlid.