I have to say that you have the best manured Koi that I have ever heard of!
Are your fish all babies,do you have an automatic fish feeder set for 1,000 adult fish,are your plants cemented into your water garden pond,is the PH in your pond crashing that your fish are so docile?? Do you not realize that koi will eat the feathery roots off of the floating Hyacinth plants, also the poisonous part of the bulb/roots,bulb is a root?? After observing the water garden that you have posted with koi ruthlessly forced to endure living in, It is obvious why your plants remain in your pond as in the stream portion? is too shallow for a koi of any size to swim comfortably. The goldfish pond that you have provided to house your koi is really not very inadequate to house koi, as they will eventually out grow such an environment and will begin to display deformities such as hunching of there backs as an example.Goldfish are programed by hormones as such to stop growing in isolated cramped conditions,while a koi grows to the size dictated by its genetically assigned adult size, not unlike that of the iridescent shark,a fish labeled a tank buster! I find you some what rude and misinformed when it comes to keeping koi at this point, As I was only trying to help a future inquisitive and very enthusiastic koi ponder in making right choices in building a proper koi pond,so that he or she could enjoy for years to come with happy healthy koi. Koi ponding and breeding is my specialty and my game!