A week ago my 18-inch Koi got caught in the skimmer net overnight. When I removed him he was severely bent. He can get around the pond in this sad condition - rise and swim (somewhat) to the bottom. With his head bent down, he appears to be eating off the bottom, then moves to other places and eats. I don't know if I should leave him alone since he appears to function to some degree or euthanize him. He is one of my favorites. He always swam across the pond to great me. He was very active before this happened.