finnaly a question i can answer. i have a whole list made of mbuna taht are small to mid sized
ill put stars by the ones taht are best suited for your tank
*-Cynotilapia afra "mbamba
*-Psuedotropheus Zebra("chilumba")("red-top")
*-Pseudotropheus damasoni
-Pseudotropheus sp. "polit"
*-Pseudotropheus saulosi
-Aulonocara baenschi
*-Labidochromis caeruleus
*-Maylandia callainos
-Protomelas sp. "spilonatus Tanzania"
*-Copadichromis azureus
*-Pseudotropheus flavus
*-Pseudotropheus elongatus "Chewere"
-Aulonocara stuartgranti sp. "Cobue"
-Aulonocara baenschi
-Maylandia sandaracinos
*-Cynotilapia mbamba
-Pseudotropheus msobo
*-Pseudotropheus tropheus
*-Labeotropheus fuelleborni
*-Labeotropheus trewavasae
-Metriaclima(Maylandia)zebra
*-Pseudotropheus acei "ngara"
*-Pseudotropheus socolofi
-Melanochromis johanni
-Melanochromis cyaneorhabdos(maingano)
*-Pseudotropheus sp. zebra gold
-Placidochromis phenochilus
*-Pseudotropheus demasoni sp. "pombo rock"
*-Labidochromis sp. "Mbamba Yellow top"
Hopefully this helps. You might want to consider asking more people about this though but i am almost totally posotive that all the stared fish are suitable. Largest of all the stared fish is like 8 inches. I left put the ones that i was unsure of and i made this list for when i was trying to fisd teh perfest fish for my tank.