We first built a pond 2 years ago. It was built in a bad place,2 very large trees overlooking the pond. I lost a good few fish to the heron,but we now have trip wire around the pond,so we have not had it in the garden this year, but have seen it flying around. We have frogs and around 15 cold water fish in the pond.8 weeks ago I noticed one of the fish was at the bottom of the pond,so I took a closer look. The fish had small worms atached to it. I went onto the internet to find out what they where. To my horror they where called anchor worms,very bad to have in your pond. So it cost me a lot to clean the pond out and treat the fish with this nasty worm. I had to buy a pond vacume to get rid of all the smelly sludge at the bottom of the pond.I had no option but to do this. Now the pond is clear and the fish look very happy with no anchor worms in site. Now as the leaves are starting to fall,we have built a large frame with a net over it to protect the pond in the winter time.I have friends who are very clever, who have just built a Waterfall with a fast flowing stream,it looks fantastic at nigh,as the pond & the waterfall are all lit upin a blue lights. PS had a parrot having a bath in the sream last week. PPS no fish or wildlife where hurt cleaning out the pond, I kept the pond water, did not flush it away.It was 2 weeks before the water clear in the pond.