I saw this question about a problem with small garden ponds, in fact one small pond just like millions of other and thought it would be a useful starting point for describing some of the anxieties and problems that small pond owners have, and dispelling some of the myths. This is more or less the gist of the problem:
I moved into a property about 3 months ago which had a small pond in the back garden. The approximate size of the pond is about 4ft x 3ft x 2ft. It had no filter, pump, or plants at the time, just the butyl liner in the hole in the ground and a disused waterfall feature. My wife was quite keen to have some fish so we put in about 20 small goldfish that we bought from a local garden centre with fish pond supplies. We also added a pump (1000 litres per hour) which I connected to the waterfall feature and sometimes switch over to a fountain. The pump does seem very underpowered as when I connect it to the waterfall there is little more than a dribble of water returning at the bottom to the main pond. We do leave the pump on 24/7. The fish have been fine for a couple of months, feeding well and seem healthy. However, now one or two of the fish have died and the others don’t seem well at all.They seem to congregate at the top near the edge of the pond as if they are gasping for air. I know that sounds daft as they are fish and don’t need air??? I would like to sort the problem out but don’t know what to buy. Do I need a filter? Do I need a bigger pump? Do I need plants (I have none). I have added two treatments to the pond, both Tetra products. One I add when I top up the water level with tap water which isn’t very often, and the other is an algae clear additive. I do live in the UK so temperature is dropping a bit now were approaching Winter….is that a factor? Any advice gratefully received… Regards Ed.
Well Ed, the good news is that you don’t need t spend any more money on gadgets from the fish pond supplies shop! Oh, is that bad news sorry!
You have too many fish for a small garden pond of that size, and as they grow they are demanding more oxygen than the surface of the pond can provide. Adding some plants may help, and will get rid of the need to add algicide which doesn’t seem like a very good idea anyway. But unfortunately, as the fish grow, with that number in the pond then there will be deaths until a sustainable population of about half a dozen is reached. It will usually be the largest fish that die first. So if you can take some of the fish out and give them away to somebody who has a a much larger pond, that would be a great idea. You could also see if teh fish pond supplies shop will take them back.
I’ve always wondered what it would take to get some good underwater pond photography pictures, and so we’ll b looking at that subject in some detail over the winter here on the Small Pond blog. To whet your appetite, here’s a youTube example of what the underneath of a small pond in a garden with a few goldfish might look like:
You’ll notice that the goldfish didn’t seem to like it much when the underwater camera was lowered into the fish pond. They went and hid under a stone. So the kind of technique we’ll need to look into more will entail leaving a camera on the bottom of the pond for some time, so that the fish and other pond creatures get used to it. That means the camera needs to have a long life power supply, and probably a remote controlled way of turning it on and off when submersed in the pond water.
If you have any experience with pond cams or underwater photography in general please can you help us out a little here in the comments?
I’m going to tell you which I think is the most useful and all round best plant for growing in small garden ponds by far. It may sound a bit of an off beat choice, because the plant I’m thinking of has insignificant small white flowers and fairly boring green leaves. It has a habit of growing up out of the water, bunching and spreading invasively. In the margins, this plant will grow quite happily out of the submerged water completely, and may even be grown in flower borders. You can eat the leaves though, after a throrough washing of course, and so by growing the humble water cress you can incidentally turn small garden ponds into kitchen garden vegetable patches! But its not just as a useful herb or salad ingredient that I would recommend water cress, it’s also very beneficial for the small garden ponds themselves. Water cress helps to remove surplus nutrients, particularly nitrogen from out of the pond water and also helps to crowd out other less wanted plant species and algae such as blanketweed and even duckweed. The only problem with water cress is that it isn’t really terrible frost hardy, and it doesn’t seem to self seed very efficiently so what you need to do is to add a small bunch with some roots into your pond each year, early enough in the season to have the beneficial effect. You can just buy a bag of water cress from Tesco or Sainsbury or wherever, eat most of it and chose a couple of pieces that have the longest intact stems with some small white roots, or even just the beginnings of roots growing from the leaf axils on the lower part of the stem. Then just place it in the garden pond in the open water, where it will float, right itself turn upside down a few times over the next few days and then start to grow and spread. Green water will be a thing of the past as the water cress acts to restore the balance in the pond. Water gardeners have in fact known about this since a long time ago, but garden pond shops seem to have forgotten about it. Water cress beds have been used as filtration systems so it should come as little surprise really that the plants helps keep water clean and pure in the garden pond, even a small one.
Water cress belong to Brassicaceae (cabbage family)
The Wildfowl and Wetlands Trust (WWT) runs an annual survey to find out how people are using the water in their homes, whether they have small garden ponds or water bodies in their garden or local area and their views on the recreational areas available to them.
This year the WWT survey is gathering information on wetlands in public spaces. So even if you don’t have even a small pond in your own garden, your story about the neighbourhood is still very important to the research.
They hope to find new ways to engage people with the great outdoors and to encourage more sustainable methods of water use. Any feedback you want to give on the survey and your opinions on water usage are also welcomed.
Greenseal Pond Liners & Green Roofs
As an incentive to get the maximum participation the WWT are giving away two small garden ponds to lucky entrants. If you win, you’ll receive all the components you need to create a wildlife pond courtesy of FLEXIBLE LINING PRODUCTS Ltd, (FLP) he UK’s leading DIRECT SUPPLIER of premium quality Roofing EPDM,Flexible Pond Liners and geosynthetic materials.
The links for more info and to the survey itself are included here below:
Miniature Water lilies are ideal for small garden ponds
Miniature or Dwarf water Llilies are a favorite for small water gardeners because they bloom profusely and add a pretty accent to the edge or when placed in the middle of a shallow pond or small water garden feature. There are now several varieties of miniature water lilies available in aquatic plant centres. All will need full sunshine and can be grown in small ponds down to about a foot and a half i depth. Their pads and flowers are small, only about a third of the size of a normal water lily’s. This makes these water plants especially suited for container water gardens as well as fully sunken small garden ponds.