Once you know which shelly you like, you can stock around their requirements. For instance, some of them (like Multies) exhibit alloparental traits and will breed in a colony, whereas others are strict pair breeders, and must be maintained as such. Some, such as Telmatochromis temporalis, are extremely aggressive and would likely dominate anything you could reasonably fit in your tank (many Mbuna included). On the other hand, some are either extremely shy (N. brevis) and/or do not maintain large territories (Multies, N. similis, etc).