They are typical mbuna of a moderate aggression level (for mbuna). Because of their frantic activity, high aggression levels, massive territories, and somewhat herbivorous diet, they're best kept with there own kind.
Calvus are territorial, slow moving, and relatively shy fish that are on opposite ends of the diet and behavior world - very bad idea. The shark... you can give it a shot, I'm not sure. I wouldn't do it personally.
