Choosing the right match of pond fish to the design of your pond is an important part of ensuring success and enjoyment of your overall pond.
Generally, ponds can be divided into three major groups:
- Water garden/natural pond
- Formal pond
- Pre-fab pond
Water Garden/Natural Pond
The water garden or natural pond has an irregular outline and usually incorporates water features like waterfalls and streams. A large portion of the pond is somewhat shallow, 1 to 2 feet, to allow the planting of pots of bog plants and oxygenating submersed plants. The center area is deeper, 3 to 4 feet, to provide space for the larger pond lily pots. Large rocks usually line the perimeter, along with other ornamental ground plants, to soften the outline, which help present the look of a natural setting. Most water gardens are a modest size, up to a 100 square feet of surface area and approximately 500 to 1,500 gallons.
Depending on how heavy of a fish load you have in the pond, you may be able to use a submersed filter or smaller external filter with a submersible water pump. Given the lack of depth and the presence of plants, this style pond does not lend itself to keeping koi. More suitable fish would include standard comets, sarassa comets, fantails, and ryukin goldfish. For a splash of quick-moving color, shubunkins may be the best choice. All of these are very hardy and should not bother the plants. If the deepest part of your pond is winter-safe, these fish can easily over-winter in the pond.
The formal pond has a distinctive geometric outline, most often as a simple rectangle. It might incorporate a waterfall and a fountain. The perimeter is uniform, usually lined with cement pavers or wooden rails. Most formal ponds have at least 100 square feet of surface area and, while parts may be shallow, a good portion of the pond is 5 feet deep or deeper. The volume is 3,000+ gallons and most often requires a larger, external-style filtration system, often with a surface skimmer overflow. This style pond makes the best use of a UV clarifier to eliminate free-floating green water, since the object is to see the fish.
The formal pond may have a few ornamental plants or even a trellis along the border to provide some partial shading during the day. Essentially, these ponds are “swimming pools” for koi. You can place almost any type of pond fish in these ponds, but they are the best design for keeping koi. The depth and volume allows for the growth and provides a cooler environment on hot summer days. They are designed to over-winter and allow the fish to remain in the pond throughout the year.
For smaller setups and even as a patio pond, the pre-fab pond is an option. Most of these are smaller volumes, from 50 to 300 gallons, are either rectangular, kidney-shaped, round, or irregular in design. Given the size, a good internal, submersed filter is often the best option for filtration. Since they are usually less than 2 feet deep, in northern climates you would have to drain the pond for winter. You can use the same types of fish as in a water garden pond, with goldfish, like sarassa comets or shubunkins, providing the most activity and color. Sometimes, two of these pre-fab ponds can be linked with a small stream between them. Another option is to use them as a smaller “upper” bog pond to act as a filter system for a larger water garden or natural pond. The bog plants will help remove the fish waste and clarify the water. Simply connect them via a small stream or waterfall to the main pond.
Please be aware that regardless of which type of pond you install, by the end of the first summer, you will want it to be bigger!