On Grass carp - I have a 12 surface acre pond in NW PA and have stocked 160 Triploid White Amur last fall for weed control. So far the verdict is still out. Seems to be less weeds so far but to early yet to make the final determination. In PA you have to do an enviromental study and get a permit for the fish. They must be bought from certain dealers and be certified triploid. The other points brought up are critical. You must have a containment system if you have a good outlet flow. Also stock the largest fish you can afford. I put in 10-12" fish @ about $10 each.

If anybody is interested I let me know, I have before pictures of my pond, and containment device and will soon know how well the fish are doing to control the weeds.