I have what appears to be a common problem of too many goldfish (50+) in what is a 5000 gallon Koi pond (6 Koi). I would like to keep about 5-6 of the nicer looking larger goldfish for mosquito control but would like to keep their breeding in check. I have access to Bluegill in the creek on my property. Do you think they would help to control the goldfish fry or am I just swapping one problem for another?