I think PVC and PVC connectors is the poster's decision, not yours. And fish tend to feel more comfortable in tanks that simulate their natural biotopes. Many people also enjoy setups that are more natural and stick to the biotope. PVC will also double as a good algae grazing media (which also covers the white of the PVC). My mbunas peck at their PVC all the time. It is not natural but it does simulate their natural nooks, crannies, and hidden passageways that their native rocks function to provide. These fish are highly adaptable but after seeing an assortment of tanks with different setups, the most natural setups tend to provide for the most natural behaviors.
Another option is the open water cichlids from Lake Malawi. These include the open water piscivores which are the reason the mbunas stick so close to the rocks. These include fish like Dimidiochromis compressiceps (the Malawi Eye-biter), electric blue ahli, Venustus (giraffe cichlid), Fuscotaeniatus, polystigma, livingstoni, etc. All get larger than the peacocks or mbunas and most have either very interesting patterns and/or bright coloration (usually blue). These require very little if any decor in the form of rock, wood, or anything else for that matter. They are used to and prefer an open water habitat.
