I keep my 8-9" BGK with aggressive cichlids like cyano, carpintis, red devil(7-8"), convicts, jd's, salvini and gold saum.
it has only been about a month that everyone has been together in the 300 gallon but all seems well the bgk cruzs the tank as it wants ignored by the cichlids, i see it often wandering the tank with the lights on. the only aggression I've seen towards it is when it pokes one of the fish with its tail as it dose its thing and that is just to move it.
before it was in the larger tank it was in a 55 with a jd, convict, salvini and some pictus cats all being grown out with no problems for months.