Hello, I need some advice about our backyard pond. It's about 30,000 gallons, beautiful pond with a waterfall that we use for swimming and admiring. A couple of years ago when we put in the pond, we added about 10 shubunkins. Now, this summer that are reproducing like mad, there must could be 100 or more fish in a variety of sizes. Does anybody have advice about how to control the population? Is there a predator fish I can add for a while? Fish birth control of some sort? Help!