Thursday, March 19, 2009
Someone asked whether we have fish in the pond. You bet we do! We inherited 4 koi in our previous house, and we grew very fond of them, so we made a pond here.
We wanted a depth of nearly 5 feet for protection from heron. We tried digging the hole ourselves but it began to fill with water very quickly and frankly was jolly hard work. We got a builder in; I assumed he'd use a machine but he sent a man with a spade and a wheel-barrow! Said man worked like a trojan and in 2 days excavated a hole so neat it looked like something computer-generated on screen.
The hole was 5 feet deep; the pond is now a little less because of its linings: first sand, then old carpet, then heavy butyl liner. There is a shelf for marginal plants along the long edge, and the liner rises and dips again beyond that to make a marsh strip. A filter keeps the water fairly clean and oxygenated. Neither our dog nor our cat have disturbed the fish; we have seen heron visit the garden (an awesome sight!) but the fish have not been killed or injured by them.
Our set-up is a compromise: it's not the koi enthusiast's ideal, because we have plants in, we allow frogs etc (which can bring parasites), and we rarely use chemicals in it. It works very well, in our eyes. There was a major problem last year when I didn't report to my husband in time that the filter pump had stopped working. Half the fish died from lack of oxygen. I later learned that fish live much closer to the margin of feasibility, in terms of how they breathe, than we do, and so oxygenation is a key point. I still remember lifting out the dead fish each time I go near the pond, but I hope this will lessen.
I absolutely love the pond. I wish we could have a waterfall but I understand this is not easily arranged because of technical problems (essentially the filter chamber is configured wrongly for that to work, it's hard to see how we could have one without replacing the whole system which would be daft).