I am setting up a 150g freshwater tank with a 30g refugium in a classroom and need some advide on what to stock. I am going to keep guppies and ghost shrimp in the refugium to have a constant supply of live food for the main tank, but cannot decide exactly what to do with the main tank. I would like to do some cichlids that are hearty and would do well at close to neutral pH. Those are my only real restrictions. Any ideas?