A Place for Fish

by Nancy Heide

After many years of consideration and urging from my oldest child, I finally decided to dig and install a fishpond. I found it was easier than I had thought it would be, and it doesn't have to cost an arm and a leg. I now have two ponds that are home to about one hundred fish. You can do it too!

Step one - choose a location. Be sure to place the pond where it can be enjoyed. For my first pond, I chose an area on the East side of my house directly in front of my living room window, which will join two foundation gardens together as one. Be sure the pond will receive at least six hours of sunlight in order to support plants and fish.

Step two - determine the size of the pond. One of my ponds accommodates a small waterfall and a few large goldfish, it is 4 ft x 5 ft and 3 ft deep at the deepest part. The other one is 13 ft x 15 ft and 4 ft deep, and it originally housed 30 small fish. Your pond can be smaller or bigger, but you may want to hire a few students to do the digging if it's any larger! I used a front-end loader to dig the large pond. The work was much easier!

Step three - remove all vegetation. I used Round-up herbicide, the fastest way. Soil neutralizes Round-up, and once it contacts dirt it is inactive forever. It will be safe to use it on your fishpond, but if you prefer to use organic methods, there are a number of ways to rid the area of vegetation. Rhubarb leaves, black plastic, or unwanted carpet scraps placed over the area will kill most of the vegetation in a couple of weeks.

Step four - dig. And dig some more! Leave a ledge around the sides for plants if you wish, and be sure to leave the sides at a 60-degree angle. This will prevent the sides from caving in, and will also deter animals from wading into the pond and catching the fish. Be sure to remove all roots and rocks, as they may tear the plastic. The most important thing to remember is to make sure the edge is level around all sides so that no liner shows above the water line.

Step five - the liner. In general, you will need the length/width of your pond plus twice the depth plus 2 feet. If your pond is 30" deep and 3 x 5 feet, you will need a liner that is 10 x 12 feet. 45 mil liner should be guaranteed for 20 years.

Step six - if you wish to install a pump, now's the time. A formula for the size of pump needed is: pond capacity ÷ 2 = required water pump output per hour. In hot weather (above 22 degrees), it is a good idea to add an air stone if you don't have a pump as goldfish can become stressed by the water's low oxygen content. An alternative would be to add several oxygenating plants such as hornwort.

Step seven - fill the pond. While the pond is filling, smooth the plastic out and keep it from caving inward. Leave the pond empty for a few days to allow any chlorine or ammonia to dissipate. To be sure, you can add a water conditioner such as Laguna's Water Prep that neutralizes both of these chemicals.

Step eight - add plants. Canna Lilies, Gunnera, Taro, Pontederia, Arrowhead, Zebra Rush, Water Irises, and Water Lilies are only a select handful of the vast choice of plants compatible with ponds. I have found that the more plants you add, the clearer your water will be. Allow the pond to stabilize for a few days after adding plants.

Step nine - add fish. At a maximum, add only one fish for every 30 gallons of water; fewer are even better. If your pond has no filtration or aeration, reduce the number still further. Also, the larger the surface area of the pool or pond, the more oxygen there will be in the water. The best time to add goldfish to a pond is in early spring after the water temperature has reached 15 degrees. If you run into a problem keeping your water clear you can add a water treatment such as Laguna's Pond Water Clarifier to clear cloudy water fast.

Step ten - over wintering. 3 - 4 ft depth should be adequate to over winter the fish in the pond in zone 4. In Killarney, we are zone 3. I over winter my fish and water lilies in the pond with a small cattle trough heater. This really cuts down on maintenance.

As a side note, I realize some of you have heard that ponds are high maintenance. Some are. My pond, however, is the most maintenance free area of my garden. It has no waterfall, pumps, or filters, and yet is crystal clear after three years of patience. The fish multiply happily and we don't feed them at all, other than unlucky mosquitoe larvae, algae, and duckweed. The plants bloom and spread, preventing algae from doing so. Snails were an addition to my pond recently, feeding on decaying organic matter. Come and see it for yourself!