One of our koi (one of two
) has gotten huge, well huge for us, about 1.5'. Since the fish usually go into caves under the rock at the bottom for the winter we were concerned that he would get stuck as he seems to swim in and has to back out. We put a mesh with 2" grin over the entrance so it blocks him and one other gold fish from going in. The other fellows can swim in and out.
Mark, would love to see the rest of your pond. You aren't related to any Mallons in California are you?