It can be done, sure. But Discus do best by themselves. Make sure the Discus are a hell of alot bigger than the Geos. Just to give em a fighting chance. Since the Geos will eat most of the Discus food you will find yourself feeding more to accomodate them. And this in return will spoil the water just enough to sour the Discus while the Geos will not be effected. Discus are Cichlids themselves and are durable to a point. But definetly need more attention than any other Cichlid we keep. Good luck Monsta.