they grow fairly slow when young, and grow progressively slower still the older they get. they're carnivorous, and like to eat small live prey, including fish. many people try to keep them in colonies, but I have a lone specimen that's kept with other Tangs and Malawis and Americans, he does fine, ounce-for-ounce is about as aggressive as a typical jack dempsey.
they can get to be a foot long but that takes many years. I got my specimen at 2" 2 and a half years ago, and he's about 7" right now.
don't keep them with malawi mbuna, unless the mbuna are a good deal smaller than the frontosa, cuz the frontosa will get bullied.