We moved to a house with an large pond with Koi. The pond is approx 40 feet by 30 feet and there are about 40 to 50 regulars (koi) that we feed and several tiny fish schools we see. My understanding is this pond has had koi for 20 plus years. The regulars we have now are approximately 18 to 24 inches.

The problem? They are rooting at the side of the pond and the pond is receding. We have to stop it and are stumped. The edges are not gradual, but the sides drop off in straight vertical clumps. We noticed the previous owner tried to plant trees for root structure, now these fruit trees are in the water. There is no liner, rather just a mud bottom. I will try and post some pictures and take some better ones when it stops raining. The sides are now receding up to the path and we don't know what to do to contain the pond.