If I had the time and money to set up a huge Tanganikan tank, I would choose the tropheus species. If I had the time and money to set up an average size tanganikan tank, i'd go w/ the alto. calvus. In my experience, tho, you can't go wrong with a good ol' oscar (or maybe a veiltail oscar). very intelligent, you can tell they recognize you, have their own personalities, and although somewhat aggressive, not really bullies.