I have been reading with interest the thread concerning raccoons and how they can destroy a pond and what can be done. So far, we don't have raccoons in our pond although they are rampant where we live. (maybe my two dachies have marked their scent around the pond and the raccoons don't like it, I don't know) We have another problem and that is herons. We lost many of our koi last summer to heron(s). They are very bold and simply walk into the pond. We have tried a fake heron (which has to be moved daily), we have 'live' dogs who roam around, and for the past winter we have netted the pond making it look like Fort Knox. I want to un-net the pond soon so I can do an algae clean up and place iris' and other plants back into it. But I am scared that once the herons notice (and they do notice when the net is off) tha the net is off, the remainder of the fish will be eaten. Has anyone tried the "scare-crow" water detractor? What about an electrical fence system whereby three rows of electrical fencing hangs out over the pond? (not very aesthetically pleasing I think) I understand that they must "walk" into the pond.