Centrals american cichlids definately. I say go for a 1000gal and up concrete tank with 2 acrylic veiwing windows. For filtration get a huge wet/dry system setup with tons of bioballs and pot scrubbies. Also you may want to put in large amounts of foam blocks for the last mechanical stage. I would imagine 2- 150g Tall would do for 2 wet/drys. As for stocking you want to go with a theme with a tank that size such as Peacock Bass and red tail cats or shovel nose cats. You shouldn't really do a couple of each fish and then just load it up with them. I would say keep the cichlids in a three family format( Parachromis, Amphilophus, Herichthys, etc.etc) Then choose bottom dwellers and then a large group of schooling fish such as Silver dollars. IMO this looks optimal in large aquariums because they're isn't soo much distraction on different fish. An aquariums is supposed to be relaxing and enjoyable not ok color, brightness, fast fish and fighting all over. If you add to many cichlids it's just going to be chaos. Especially with less aggressive cichlids or rays with big mean FH and Guapote. Find a new stocking plan but keep it to a minimal and find certain species that will do good with each other.