I had a green terror several years back. He got about 8 inches and started trying to kill everything in sight. Took it to a LFS to trade in and he bit a hole in the bag on the way to the store. Good looking fish, but got a little mean. I was new to cichlids then and had a combination in my tank that should never have worked. Except for the green terror, most of them got along.
Most aggressive fish I have had was a Jag/Dovii hybrid, 14 inches long. I loved him, though. My first real monster fish, and a bit of a challenge to keep. I had him almost 2 years before I lost Jag.