The tank is a little small because of the aggression of the Brichardi. The main problem is the different water conditions these fish like, Kribs in the wild live in areas with a pH in the low fives and almost no hardness to the water. Brichardi live in water with a pH around 8.5 and very hard.
Tank raised fish are quite adaptable to different water types but the aggression of cichlids in a small tank can result in dead fish. My Pelvichromis sp. Blue Fin can keep every fish in a 65 gallon tank at the other end when they spawn.