It is possible to hire someone to do pond maintenance, just as one can hire someone to build the pond. But one of the great things about ponds is personal involvement — planning, constructing, maintaining and enjoying the results. Much of the effort needed to keep a pond healthy for plants and fish is determined at the very first step: planning.
Typically, much of the discussion when planning a pond is about aesthetics: how big the pond should be, what shape, which materials and so on. These are obviously important concerns, but planning also includes making future maintenance as easy as possible. So in essence, pond planning is also about pond maintenance.
Many natural ponds are fed by streams or underground springs, but ornamental ponds are closed systems. The water you add is the only water in the pond until you add more to replace evaporated water (unless it rains). In other words, the fish and plants in your pond will do well or not, depending on whether the water quality is good or not good. Water quality includes concentrations of dissolved compounds, and levels of oxygen and carbon dioxide; temperature is also a consideration.
In ponds, filtration can be optional, depending on the number and size of fish, and water changes are usually not convenient. Unless a pond is constructed so that there’s some means of releasing or pumping water out and a system for disposing of this water, the water that goes into the pond stays in the pond.
Given all the effort that goes into planning where the pond will be, along with its size and shape, the one thing rarely taken into consideration is access to the pond (and associated equipment) for maintenance tasks. Visions of a pond nestled into a corner — lush with aquatic plants and surrounding landscaping — are certainly attractive, but they won’t become a reality for long if one can’t get to or work in the space (if any) available around the pond.
The more difficult it is to actually do maintenance, the greater the likelihood that maintenance will be put off or even ignored — at least until the results of such neglect are all too obvious. In addition to access to the pond perimeter, the width, length and depth of the pond are also factors in accessibility.
Feeding the fish doesn’t require much in the way of access, but when it comes to plants, you will find yourself wanting sufficient room to add or replace plants, prune them as necessary, and move them if they are not getting sufficient sunlight to grow or flower. Pond sides should be steep enough to discourage animals from entering the pond, but add a shelf or two along the perimeter where you can place pots of aquatic plants. Even if your primary interest in a pond is fish, plants both in the pond and around it do matter. Plants make the pond far more attractive; they offer shelter for fish from predators and intense sunlight (particularly water lilies); and they consume dissolved nutrients, which helps limit issues with excessive algae growth. Plants around the pond also make it more attractive to wildlife, such as frogs and other amphibians, as well as birds, by offering cover for these creatures.
To help reduce algae maintenance issues, include one or more bog areas in the pond. These are shallow areas that are heavily planted and have water slowly flowing through them. Dense plantings are known as vegetative filters because they consume large quantities of dissolved nutrients from the water. If you have sufficient bog areas, you may not need a filter. Garden ponds (which have no fish or only very small fish) typically do not need a filter but may have a small in-pond pump to circulate water and prevent stagnant areas in the pond.
You may decide on an actual filtration system for the pond if you are going to have large pond fish, such as koi and goldfish, and want more than a small number of them. A filter to process fish wastes can help maintain better water quality. However, pumps and filters require maintenance, as well. The screen or sponge filter that protects the pump intake will need cleaning weekly. Filters with mechanical media to remove particulates from the water will clog, which will reduce filtration, so easy access to the filter is essential. In addition, as a filter becomes loaded with organic material, it actually becomes a source of dissolved nutrients itself. For all these reasons, you may wish to locate the filter outside the pond, using piping to move water from the pond to the pump and then back. This will make weekly maintenance somewhat easier.
Everything up to this point has been to ensure easy pond access for maintenance and to include design features that will increase water quality while reducing maintenance. But some maintenance tasks remain.
As already noted, summer is the season for the most maintenance. This makes sense, given that all biological processes in the pond are at a maximum during these months, aided by more direct, intense sunlight. Summer is both a time to truly enjoy your pond and a time when you will want to spend more time tending to it.
Although pond location might not seem relevant to maintenance, it is a big factor. Specifically, the amount of sunlight (and therefore also water temperature increases) is controlled by how much shade or lack thereof that the pond has. In winter, the sun crosses from east to west much further south, but in summer it’s basically directly overhead. The only shade is that from the house, trees and fences.
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If you want flowering aquatic plants, the pond — or at least some portion of it — needs at least six hours of sunlight each day. Keep in mind that all that sunlight will drive the growth of algae. Even with a lot of other aquatic plants, the nutrient levels may exceed the amounts the plants can use. This is almost certainly true if there are a lot of fish, particularly big fish. If you can reduce the intensity and duration of sunlight, you can exert at least some control over the proliferation of algae. In terms of maintenance, try to remove as much algae as often as you can.
Location may turn out to be a critical factor in how your pondkeeping endeavor works out. Trees are very good at shading a pond at least part of each day. Leaves and needles from the trees will float for days but will eventually settle to the bottom. Some forms of aquatic life may actually thrive from the leaves and needles, but this material can also leach tannins that color the water with a brown tint (which is harmless) and will add to the dissolved nutrients in the water from decay. Just remove leaves and needles from the surface as needed.
When it comes to pondkeeping, it wouldn’t be unreasonable to consider fall, winter and spring almost as one long season with three parts. All maintenance tasks are centered on the cooling water of fall, the low temperatures (in particular, freezing) of winter and the warming of spring. Maintenance depends on where you live, but other than tropical and possibly Mediterranean areas, the fish and any non-native plants need to be brought indoors (in a space that never gets close to freezing).
While it is possible for fish to survive winter in the slightly above-freezing water just below the ice in a pond (assuming the pond is deeper than the frost line), they often do not do well and may not survive even if the water doesn’t freeze. Keeping a pond free of most ice is an expensive proposition at best and still may not help. With planning and help, removing fish is not excessively difficult. In short, you need sufficient vat space in a basement or other location that contains enough water, plus filtration for the fish. Given temperatures in the 40s or even 50s Fahrenheit, the fish will not need to be fed, so the only real filter you need is biofiltration to deal with ammonia from their gills.
The most difficult aspects of this process are lowering the water level in the pond, netting the fish, placing each one in a water-filled container and then carrying it to the vat. If you put off this task until the weather is much colder instead of mid-autumn, there is the possibility of spilled water freezing, creating a potential slipping hazard.
Unless the pond plants are native to your area or a region with similar weather, they are probably tropical. These need to be brought inside (cool but not freezing) and wrapped in newspaper until spring. The pond can be emptied and the leaf litter removed. Concrete ponds should be emptied to prevent frost heave cracking, and above-ground ponds must be emptied because the water will freeze and expand, damaging the pond.
In the early weeks of spring, there is little actual maintenance. When the water warms into high 50s to low 60s, the fish get to go back outside, as do the plants. Due to cold temperatures during the winter, biofiltration is slow to restart unless the water is warm enough, which is why I recommended making sure the pond water has warmed before bringing the fish out.
The Balance of Natural Ponds
Ornamental ponds do not have the biological complexity of natural ponds, and they don’t have the balance of fish to plants that real ponds do. In natural ponds (except perhaps high-elevation mountain ponds), plants represent some 90 percent of the biomass in the pond, and fish are most of the remaining 10 percent. There is a “balance” of life in the pond, which includes the limitations of pond size and water volume, as well as food availability. Fish populations and fish sizes are controlled by predation, disease and starvation.
In the typical backyard pond, this ratio is reversed. If you want a garden pond, which means a lot of plants and very few (and very small) or no fish, you can probably avoid the vast majority of maintenance that is usually essential to keeping a pond healthy. In ponds with high densities of fish (and large fish), a lot of filtration and maintenance are required.
Water Changes and Conservation
The availability and cost of water to fill and refill ponds is limited in many places. Water conservation policies that set limits on usage and tiered pricing to make excessive use unattractive are common in many areas — particularly in summer, which is also the season for most pond maintenance tasks.
Summer is also when the levels of dissolved nutrients from fish waste, combined with warmer water and more intense sunlight, will result in the growth of algae in the pond. When water changes (which help reduce concentrations of dissolved nutrients) cannot be done, the pondkeeper has to use other methods for dealing with this potentially huge maintenance task.
The most effective alternative methods for reducing nutrients in the water are to use a lot of plants and vegetative filters, which are heavily planted shallow areas with a slow water flow.
Easy pond care is maintenance that’s easier than it would be if there are issues with getting to and working around the pond. Ornamental ponds are not real ponds (and by “real,” I mean natural ponds). Because of this, maintenance is a necessary part of having a pond, and this becomes even more true when there are fish in it. If you set aside time each week for maintenance, it will be both easier and more effective than putting it off. It’s almost impossible to have a maintenance-free backyard pond, but with planning and attetion to details, you can come close.
Miller Morgan has been involved with pondkeeping and writing about it for more than 25 years. He lives in Southern California.