From my own experience, Jewels are able to cope with rift lake company, subject to the individual fish in question. A less aggro jewel may do well physically but not show that beautiful colouration for you. Diet/water is not a problem. Ideally if you put them with mbuna it should be with the less aggressive types, and it would be wrong of me not to acknowledge that plenty of respected experts say you shouldn't do it at all.
