"I wouldn't imagine it would be too good for them" is a definate understatement. 10 gallons is not nearly adequate for most of the Rift lake Cichlids, especially if talking Mbuna. I know 'cuz a buddy of mine once tried it (against my suggestions). He put a Ps Acei, a Convict, a Red Zebra and a very beautiful Cynotilapia Afra Cobue. They were ok for about a day. In under 2 weeks he had a lone Cynotilapia. I talked him out of said fish and he now resides happily in a 55g and is still top dog. These are fish that naturally claim territories in the wild. They are very active fish, they are vicious with rivals and to have 2 in the same tank they would compete for everything, food, space shelter. Not only that but the bioload on the filter would be really heavy once they started maturing, even for a good high flow filter. They would probably not lead very long lives. Maybe try some Tanganyikan shellies, some of the smallr Julies or the Multis would be good. Or you could go the American route and try some Rams or Apistogramma something.