Just built a new pond late last year (approx. 5,000 gallons) to house koi and my wife and son "surprised" me with about 10 feeder gold fish. Now I have about 400 gold fish. We have been trapping them (slow going) and releasing in to a neighbors large natural pond (with his permission) but I am looking for a permanent solution to control this population without disturbing the koi by chasing gold fish all over the pond with a net. Could I throw a bluegill or two in there or something like that or would they damage the koi (currently 6"-8"). Thanks in advance!