Steve B: I don't think the Amur is the same carp that is taking over the Great Lakes. However, to emphasize, they are supposed to be sterile, so you need to buy from a licensed seller, if you decide to use the Amur fish. They have grown to be 4 feet long after a very long time in our pond from feeding on algae. They start off very small - I suspect they will grow according to the amount of algae that is available. Anyway, something to consider when you get your pond under control and stable. Works wonders for our pond.