I have a 75 gallon tank stocked with 12 Malawi cichlids. Included in the tank is one Demasoni cichlid (the largest of all the fish). He is claiming 80% of the tank as his own. The other 11 fish are at the corners and are all being chased around by this guy or gal (don't know if it's a male or not). Should I add more fish to disperse the aggression? If so, how many? Should I rearrange the tank? Should I do both? I don't want to overstock the tank. I went on Youtube a couple of days ago and saw a video of 55 gallon tank stocked with 70 african cichlids and was appalled. My water conditions are pristine (0 ammonia, 0 nitrites and 0 nitrates). Please advise. Thanks.