The shell dwellers are from both Lake Malawi and Lake Tanganyika (perhaps others, too?). The most famous example is the Tanganyikan Neolamprologus multifasciatus
. The Maylandia livingstonii
is the most famous Malawi example (almost got some myself), but they do eventualy grow larger (3-4 inches) and abandon the shells.
You're right to think that a Malawi or Tanganyika biotope is the best way to go (I'm building one for one of my professors ATM) in terms of pH and compatibility, but the lines don't have to be drawn firmly between the two lakes. Keeping Malawi and Tanganyika cichlids together at a pH of 8.5 or so would be fine. I *am* a purist, so when designing this tank, I'm going for all Malawi!
Most ppl, myself included, would advise this.
Read up *thoroughly* on African Cichlids, though, if you haven't already. It sounds like you might be adding 1 member of a species only. This does sometimes work, but in general you should try to combine 1 male of a species with 3+ females. This minimizes aggression which can, in any AC
tank, be a big issue. Yellow Labs are no exception, though they are far from the worst (I'm looking at you Auratus, Johanii and Compressiceps
). Also, YLs are a great fish to have 4-5 of, as both males and females are very bright and colorful.
Obviously your sense of aesthetics will lead you towards diversifying the characteristics of your fish. This is a good thing! AC
species that are too similar in body shape (morphology) or color will pick fights with each other. Try to get some blues, some yellows, some stripes, some peacocks etc.
Don't overstock the tank... 3 species is the max you'll be able to keep, probably.
One last really important thing to keep in mind is that M'bunas and Haps (different "flocks" from Lake Malawi) have very different dietary needs. The best route to take is to not combine the flocks. If you place M'bunas in with Haps, you'll find that the protein-rich food the Haps need is too difficult on the M'buna digestive tracts (they eat "aufwuchs," a combination of algaes and other aquatic veggie material). They will get "Malawi Bloat" (intestinal blockage) and die...
I've found www.malawicichlids.com
to be an invaluable resource. It is scientific and incredibly helpful. Check them out if you haven't already.