I've been trying to find a new home for this guy, but haven't had much luck. Its a 12" Shubunkin goldfish. It was living in my 210 gallon with my cichlids, but I had to remove it due to aggression. The goldfish was chasing around and attacking the cichlids. some of these fish were almost as big as it was. He tore up my adult red line severum pretty bad, so I finally tossed the goldfish into a 55 gallon tank by himself. I'm hoping to find a nice koi pond he can go into, but at the same time I'm afraid he will kill his pondmates. any idea why my goldfish is so mean?

I have a pond big enough for him.