[Ebook] Encyclopedia of Aquarium & Pond Fish – Introduction to Pond Fish – What to consider

Introduction to Pond Fish

What to consider

A carefully chosen and well-designed pond can be the focal point of a garden, but finding the right style can be a daunting task. The choice of design is partly personal but should also take into account the requirements of the fish, as well as the amount of space you have available, the existing landscaping in your garden, your level of building expertise, and the amount of time and money you have to spend.

Although the basic construction techniques used to create ponds of any type are similar, the resulting effect created by the landscaping and planting can be strikingly different. Ponds can be designed in an informal, naturalistic way or in a formal style, based on stark, geometric patterns, such as rectangles.

A good starting point when deciding on the type of pond to build is to consider the species of fish you would like to keep. Goldfish are suitable for most types of ponds, but large pond fish, such as koi, require a considerable volume of water if they are to thrive. A pond for these fish must have a minimum surface area of at least 100 ft2 (10 m2 ). The constraints created by keeping koi mean that they are invariably kept in a larger formal design of pond. Such ponds are costly to construct, however, not just because they need to be large but also because they require an effective filtration system to maintain water quality and clarity.

Naturalistic ponds are simple and inexpensive to create using flexible pond liner (see p.302). At certain times of year, however, the fish may not be particularly conspicuous in this type of pond; during early summer, for example, the water may be green with algae and the pond partially covered with profuse plant growth. A filtration system is less essential in a pond of this type, but regular maintenance is required to remove dead plant material and clean out silt.

Depth is an important consideration, especially in temperate areas. Fish instinctively retreat to the bottom of a pond as the temperature drops toward freezing. Ponds should therefore include an area that is at least 4 ft (1.2 m) deep, to ensure that it will not freeze to the bottom in even the most severe winters.

SITING GUIDELINES

• Ponds should be constructed only in areas where the ground is relatively level.
• Choose a location that allows you to view the pond from inside the house.
• Consider the availability of a power supply for running filters and fountains.
• Avoid building a pond close to trees, because the growth of their roots may damage the foundations or puncture the pond liner.
• Avoid areas that are naturally prone to becoming waterlogged, because excess water can collect under the pond liner.
• Site the pond in a sheltered spot, to stop leaves from blowing into it.
• Choose a site that is not in direct sunlight during the hottest part of the day

Construction choices

The availability of modern pond construction materials provides a wide choice for the hobbyist. Creating a pond using flexible pond liner or installing a preformed pond unit (see box, below) does not require advanced construction skills and can be relatively inexpensive. Large concrete ponds, by contrast, are considerably more expensive and may even require the services of a professional installer.

A wide range of flexible liners and preformed pond units are available to suit most budgets, but it can be a false economy to purchase the cheapest option. Less expensive liners, such as polyethene, may not last as long as higher-quality flexible liners, such as PVC and butyl rubber, which are more resistant to attack by the ultraviolet component of sunlight. Butyl rubber is probably the best material to choose, partly because it is very elastic and so will not crease as much during installation as other materials. A PVC pond liner is a somewhat cheaper option, with a correspondingly shorter life span; if choosing PVC, select a thicker grade, typically 1 mm, with a reinforcing nylon weave providing extra strength and durability. Preformed pond units are also available in a range of materials, of which rubberized versions are generally the most durable.

Flexible pond liner is sold by the square foot, in rolls of various widths, so careful planning is required to be sure you purchase sheeting of the correct dimensions. The amount of liner required is easily determined for any shape of pond using the following method. First, determine the length of the pond at its longest point and the width at its widest point. Next, adjust these dimensions to allow for sufficient liner to fit into the deepest part of the pond: to do this, multiply the maximum depth of the pond by two, and add this to both the length and width figures respectively. Finally, add a further 18 in (45 cm) to each dimension to provide extra liner to overlap the edge of the pond; the final figures give you the overall width and length of liner required.

FLEXIBLE LINER OR PREFORMED POND UNIT?

FLEXIBLE POND LINERS

Building a pond using flexible liner is relatively straightforward and allows you to exactly tailor the design to your needs. All types of liners must be used with a suitable underlay material, which cushions it from sharp objects; commercial products are available, but large pieces of old carpet or a layer of sand can work just as well.

PROS

• Can be used to create any size or shape of pond and is ideal for a more natural look.
• Durable; top-quality liners can last for up to 50 years before needing to be replaced.
• Suitable for use either in the ground or raised above it within a brick support.

CONS

• Can be punctured quite easily by the roots of some plants, requiring repair.
• Cheap liners can have a short life span and are a poor choice.
• Requires underlay, which can add to the cost.
• Silt can build up in folds or creases in the liner and can be difficult to clean out.

PREFORMED POND UNIT

Preformed units made from plastic, fiberglass, or rubber are quick and easy to install and are manufactured in a wide range of shapes and sizes. Many designs include a shelf around the edge for cultivating marginal plants. Pale-colored units should usually be avoided, because they can look artificial.

PROS

• Very easy to install, once the area has been prepared.
• A wide range of shapes and sizes are available, including units that are large enough to accommodate koi.
• Can be used both in the ground and for creating a raised or semi-raised pond.

CONS

• Units are molded to fixed shapes, which can constrain pond design.
• Some styles may not be deep enough for safe overwintering of fish.
• Fairly durable, but if split or otherwise damaged by invasive plant roots, they are not easily repaired.

POND SAFETY

Safety should be a prime consideration when designing a pond that may be visited by children. A raised pond is a safer option than one at ground level, and there are rigid wire grilles that can be securely fastened over the top of the pond. Even with these measures, however, children should always be supervised near the pond.