I agree they are still of a nature capable of that friendly curiosity in their caretakers goings on and being social and charming in the way the less predatory cichs are. I have had several midas and in spite of their badassness they are usually fairly capable of harmonious living in the right adult community. I went ahead and reintroduced them anyway one at a time after a night in a dark ten gallon and let them each individually ake a little slapping around and things have returned to normal mischievous play in their area of the tank with an occasional poke at the big guy to which he responds with either a dart out of his lair to stand motionless and stare at the pain in his ass til he scoots off or a light speed chase around the tank ending exactly where it started. The contrast in their personalities is enjoyable again and not at all frightening like what went on before I removed them. They should be fine another few weeks. Jaguar back too and seems delighted to be out of the harmonious and active mixed tank. She's getting her own 120 next week. I hope I can find her in itI keep my midevil in a 100 gallon by itself, my dovii was in a 125 g growout by itself, my 5" jag is in a 75 with only a striped raphael that is larger than it and very well armored. Even grow outs of highly aggressive species will stake out an entire 4' tank as their own. I would not attempt growing out that mix even in my 210 without using dividers. I think you should just keep the red devils, they will require an upgrade sooner than later, but not as much of one. They are also more interactive from a younger age.