Some good points already. Totally different thing between some of the large, meaner CA fish, some of which can only be kept by themselves in a tank or as a pair in a divided tank (unless you have a very large tank) and typical Malawi predators. Lot of the larger Malawi predators are actually (relatively) peaceful (aside from eating smaller fish) and not much problem to keep in a male display tank. Typical Malawi rules apply-- best to keep them in a group setting to minimize aggression-- but you don't have to crowd them like you do mbuna, and really shouldn't crowd them to the same extent, meaning tank size is a factor to keep these typically larger cichlids.
Naturally, like most Malawis cichlids, you can always get an individual stinker and territorial behavior or aggression increases when spawning or courting females. I've seen many nice Malawi predator tanks, they make an impressive display in a large enough tank.
As far as Lake Tang, the primary piscivore (fish predator) in the hobby would be cyphotilapia, which may or not be predatory in a tank (very often not, but you never know) and while they have their own quirks and requirements, they are, again, nothing like big CA nasties.
