I typed up a great response then hit delete ..argh !! I'll give you a short version then expand lAter lol
So as I'm sure researching you've found mbuna are best with mostly if not all mbuna . I hope your rusty's pump out a tank boss ! They turn brilliant purple when they are the dominant fish !
You're options for additions are pretty darn open within mbuna fish. White labs (tumbii reef) would be very pretty to add to your colors , chailosi I think would look nice and work well , white top hara's are super cool ( very mean though but then again your afras may be pretty mean as well and it's ok.. That's just mbuna being mbuna ).
Looks like decent filtration 👍👍
You may want to consider a power head to beef up the flow as they are from highly turbulent waters . Keeps them from being absolutely murderous lol.
They are mostly herbivore however NLS cichlid pellets have proteins they can digest . Fresh zucchini clipped on the aquarium walls will be well appreciated .i also add a few types of saltwater herbivore frozen fish foods. And some other ransoms
Have you added salts yet ?
They are from one of the highest salt content freshwater lakes in the world and really do best with salt. Not other PH chemicals ! For my 72g African tank the ratios I've found to be ideal are 4table spoons Epsom give or take , aquarium salt as directed by the box , and 1 cup(or a little more ) of marine salt . Then on water change days I only replace the percentage if those salts I took out calculated by the percentage of water I changed. Speaking of.. I need to change the water for my Africans right now lol.. They're looking like they're in a bad mood .. Twerps ❤️ Sent from Petguide.com App