Good Post! I usually hear more from people worried about chemicals than with introducing non-native species to a pond. After doing fish sampling on the Mississippi River, I can tell you that just about everything anyone has put in a pond has escaped and somehow bred. Not all states are stringent on having sterile species. Big Head, Grass, Black, and Mirror Carp were all captured in our nets. What this will mean to the paddlefish, young of other fish, and what's left of our aquatic vegetation in the few backwaters left won't be good. Not to mention what Eurasian Milfoil, Curly Leaf PW, and Zebra Mussels are doing. Chemicals have been used for decades and have been under the microscope the whole time. If used sparingly and according to the label, a certified chemical applicator can definately maintain a healthy food chain and increase the users enjoyment of a pond or lake.
Robert B