8-10" - White amur, or grass carp, are stocked to control aquatic vegetation. They are more slender and longer than the common carp and unlike common carp are unable to reproduce (sterile triploid). Stocking rates vary depending on the amount and kind of vegetation in the pond. Pond owners should not expect white amur to take care of a vegetation problem overnight. They will eat more as they grow older and bigger and make take a year or two to reduce plant growth.