I have a 180g tank setup for african cichlids. No malawi or anything like that, just a colony of frontosa and some passive haps. I want to get some predators for the tank that wont really bother anyone else and wont be bothered. I already have a polypterus in there and plan on getting two or three more. But is there anything else that would go alright with Frontosa and survive the alkaline enviroment (its usally at 7.8).