That is Heterotilapia buttikoferi. It is commonly known as a Buttikoferi or just Butti.
An older common name was Hornet Tilapia but I don't think this name ever caught on and is really not in use today.
Gets very large, quickly. Can get well over a foot long.
It is considered to be one of the most aggressive cichlids. Might tolerate tough , small fish like mbuna, but probably won't get along with any other large cichlid it sees as it's competitor.
Wow, what a beast!
How big was that one? Usually people see these things at small (baby) sizes in the Fish Store, and get all excited by the cool black and yellow coloration.
And yes, those things at that size do look pretty cool! it's later on, when they just keep growing.
And the body count in the aquarium with thrashed fish just keeps going up and up. And well, the idea of keeping an African Riverine Herotilapia buttikoferii, is probably not going to go as originally planned.
When they reach the ultimate coloration stage of dark, dusky grey as your pictured one is - the ultimate mature size for this Cichlid is close to being attained.