Cichlidophiles know very well that tanks containing multiple cichlids will invariably have a tank boss. This will be the apex cichlid, the one that none of the other cichlids can bully, but it won't necessarily be the largest in the tank. Among other things, who the boss becomes will depend on the mix of species in the tank and their genders.
My 75g is no different. It's a mixed Tanganyikan tank that, at present, contains 5 different species of cichlids (A. calvus, N. leleupi, T. vittatus, C. macrops, J. marlieri), three species of dithers, and a couple of species of bottom dwellers. The tank boss is a male Altolamprologus calvus, one of three calvus in the tank (2m, 1f). However, I've discovered that the tank has an associate tank boss...and it's not a calvus.
Below is a photo of the associate tank boss. What he lacks in size, he makes up for in tenacity. He just generally has a bad disposition. As far as I can tell, he hasn't really carved out a territory. He just roams the tank doling out cichlid justice to pretty much anything that crosses his path. He's not killed or injured anyone yet, but he's certainly sent the entire population in a panic when he zeros in on someone...except the boss calvus.
The Cichlid Room Companion
Tropical Fish Hobbyist
American Cichlid Assoc.
African Cichlid Hub