I am going to be setting up an aquarium once I move in November. I'm hoping for a tank that's 55 Gallons or larger. I have been researching and looking for various types of fish. I really like the appearance of the blood parrot cichlids, but know that they are aggressive. What other fish could cohabitate with them? (I know they would have to be around the same size). Also what is the process for nitrogen cycling the tank? This is my first large aquarium. Thanks.