Congratulations on understanding you shouldn't mix mbuna with haplochromines or Aulonocara. You would be staggered how many people do this, and then wonder why there's carnage in their aquarium. The exceptions are Labidochromis (e.g., yellow labs) and Iodotropheus (e.g., rusty cichlids) which get along very well with Aulonocara.
Aulonocara are much more deep bodied than mbuna, with a somewhat triangular rather than rounded head. Aulonocara generally have numerous vertical bands on their flanks, especially the females. Because Aulonocara hybridise readily, you need to trust your retailer if you want good quality stock. For obvious reasons, serious cichlid keepers only maintain a single species of Aulonocara per aquarium, but some casual aquarists mix them, and the result is hybrid offspring that get dumped in pet shops. Avoid anything sold as "mixed peacock cichlids" or "mixed African cichlids". These will almost certainly be hybrids.
Unless you have a really big aquarium, you're going to keep just one male and a couple of females, so you may as well pay good money for some top-notch, wild-caught or F1 specimens. Once they're breeding, you'll easily make your money back with the offspring. Note that some Aulonocara are prone to becoming hyperdominant, so choose your species carefully and stock sensibly.
Mbuna are rock-dwellers, while Aulonocara mostly live in the transitional zone and feed in open water. If you design the tank right, you can keep, for example, Aulonocara baenschi with some Labidochromis caeruleus and have a stunning collection of colourful fish that don't fight and won't hybridise.
Cheers, Neale
