it might help, but discus should be in groups of six or more. no, it does'nt matter which type, but you have to realize that you may just have a bully. they are still cichlids and that is what they do. sometimes it takes a while for them to get thier pecking order. how large is the tank? with the Aro it should be at least 6'. if not then you may never stop the aggression. discus are shy fish and while there may not be any aggression between them and the Aro, they will still stay away from it and probably not use the whole tank as they should. I had that problem when I added 4 festivum's to my wild discus tank. no aggression but it was stressing the discus. add a couple of more and hope for the best.