The frontosas are tanganyikan but definately too big for your tank. I'd say Tangs all the way but I am biased- I don't like malawis as I just don't see the fascination with lots of big, ugly although colourful fish that all look the same with few acceptions. You have haps or mbuna and that is about it(straps on tin hat) . Anything slightly interesting looking is usually predatory so you end up with a tank full of them instead. If you want a tank full of biggish boring fish you may as well keep goldfish, they are cheap and easy to come by- similar to a lot of malawis . Many tangs stay small, have more interesting colours and body shapes and also have better temperaments (plus if you manage to breed them I can bum some fry off you!). Before any Malawi fans jump on me please know that this post was only in jest (mostly) and I know you are happy with your pretty (boring) fish.