Do you want a pair or just a single fish, or tankmates as well.
For a pair I wouldn't house them in anything less than a 30 gallon, they are very aggressive towards each other and other fish. If you want tankmates you're looking at a big tank, especially with a pair. And even then they would have to be chosen wisely.
They are technically african cichlids, but behave more like most CA cichlids than mbuna or the like. So if you're looking for personal experience with them might be better posting in the african section.