A pond is like an outdoor aquarium. Some of the routine care is easier because there is more natural filtration with greater amounts of incoming fresh water and outgoing dirty water. It is also somewhat closer to the conditions you'd find in the natural ecosystem. However, the natural elements will constantly impose themselves on your pond's pristine order, and removing the debris and sheltering it from inclement weather conditions will take somewhat more effort as well.
Spring
This is a time of renewal after the harshness of winter. It is also the time to start or to reestablish your pond. Use a flexible pond liner or solid preformed pond. Place in a sunny area where it will get at least six hours of sunlight each day, but away from the trees and bushes. It will also have to be within reach of a garden hose and electrical line.
Determine how many gallons you'll need for your pond to know how many fish you can stock. It is also necessary to know how many gallons your pond will hold to make water changes and to add conditioners, food, and medications. Calculate the number of seconds it takes to fill a five-gallon bucket with a garden hose, then do the same for your pond, filling it at the same flow rate. Now take the number of seconds to fill the pond and multiply it by the number of gallons in the bucket, then divide by the number of seconds it took to fill the bucket, and you'll get the number of gallons in the pond.
If the pond has already been filled, then measure the length times width times average depth in feet times 7.5 to get the number of gallons in a square or rectangular pond. For a round pond, take the top diameter times the bottom diameter times the height in feet and multiply it by .785 to get the volume.
After filling the pond and before adding fish and plant life, condition the water to neutralize the chlorine or chloramines and heavy metals found in tap water. These substances make water drinkable for humans but are harmful to fish and plants. Each time you add water to the pond, it also will have to be conditioned. Water conditioner also protects against too many nutrients and waste in the pond caused by overstocking. In addition, a stress coat should be added to the water to maintain the fish's protective slime coat. Consisting of aloe vera, the stress coat replaces and heals the coat that the fish loses during times of stress. Add pond salt to the water to give the fish the needed potassium, sodium, magnesium, chloride, and calcium for proper electrolyte balance.
Next, you'll need to filtrate the pond. Start with mechanical or manual filtration of pollutants. Use foam pads in the filter to trap particles. Chemical filtration removes pesticides, waste, and nutrients via filter carbon, activated carbon, phosphate remover, and ammonia chips. Biological filtration converts ammonia and nitrite into less toxic nitrate on special media so that beneficial bacteria can thrive. Nitrate is used to supplement aquatic plant life as part of the nitrogen cycle. In addition, commercially prepared beneficial bacteria can be added to a new pond to get the process going. All three types of filtration are necessary to keep the water clean and clear.
If your pond has already been established, to restart the system, clean debris from the bottom of the pond and skim the surface. Check filters for cleaning and repair, then restart them. Test the water and add pond salt to help your fish develop a slime coat and overcome the cold months and temperature changes. Use a bacterial additive to get your biological filter going. Connect the water pumps as soon as overnight temperatures are above 50 degrees F. As soon as the ice has thawed, add an aerator to oxygenate the pond in case of a bacterial bloom.
A water pump creates water motion and adds oxygen to the water that is crucial for your fish. This can be provided by circulating the water or by use of an actual fountain. The pump needs to be able to move the pond's entire volume around every two hours. Divide the number of gallons in half to get the correct flow rate. Also consider how high the water must flow above its level for a stream or waterfall. Add a pre-filter to protect the pump from leaves and debris that fall into it.
When the temperature reaches 70 degrees F, add oxygenators and floating plants. Cover half the pond with plant life. Plants provide protection and spawning space for your fish. They also eat nutrients and provide shade, which prevents algae growth. Plants also provide oxygen that fish need for survival during the day through photosynthesis. Floating plants grow with all or part of their foliage on the surface. Submerged plants grow beneath the surface. Marginal or bog plants grow in shallow water with stems and leaves above the surface. Use all types of plants for their various functions in your water garden. By potting plants, you can remove them for storage and reposition them as needed. The pH level must be checked and adjusted for proper plant care. A range of 6.8 to 7.8 is recommended. Monitor the pond's temperature and test the water quality on a regular basis.
Aphids attack plants during the growing season. However, insecticides are harmful to fish. Use of an herbal control can do away with aphids without poisoning the water. Plants also require nutrients to help them grow and flower. Add plant nutrients that contain trace elements missing from garden ponds for year-round growth and color.
Now you are ready to stock your pond with fish. Add no more than three to four inches of fish per square foot of pond surface to avoid toxic buildup. In cooler weather, when fish metabolism slows at water temperatures of between 42 and 72 degrees F, reduce the amount of protein and increase the carbohydrates you feed the fish. A diet formulated for cooler or for warmer water temperatures should include all the vitamins needed for proper growth and development.
Although beautiful, Koi fish are large and expensive. Goldfish also are beautiful and are a popular alternative for their ease of care and reasonable price. Some warm-water varieties will need to be taken inside when the winter hits. The cold-water types can remain in the pond all winter. Make sure that the fish you choose come from clean ponds or aquariums and are lively and colorful. A quarantine tank is recommended for use for a few days so as not to introduce disease into the entire pond. The fish may not eat for a few days while adjusting to their new surroundings.
Spring is the time to clean and inspect your pond. At 42 degrees F, the fish will start to eat again and the water will need to be changed over several days. Feed them wheat germ at this time. Remove dead leaves and debris from the winter. To maintain your pond, change 15% to 25% of the water every month. An enzymatic cleaner in addition to water conditioner and stress coat will help to keep the organic matter down and the clarity up. Restart the filtering and change the filter media. Use pond water to clean the filter media so as not to kill off good bacteria. Check for the presence of ammonia and nitrite every week. Follow the directions on your test kit for adjusting any spikes in toxic substances. After the stress of winter, make sure your fish are given antibacterial medication to heal damaged fins and fin and tail rot.
Spring is also the time when algae blooms, prior to plant growth. Algal blooms are caused by excess phosphates and nitrates that come from tap water, rain runoff, fish waste, and debris. Adding a sun block will inhibit this growth. Barley straw is a natural product that takes time to fight algae. Place it in a container of moving water in your home six weeks ahead of time so it will be ready for your pond. If nothing else works, use an algae remover to cure the pond of green water, blue-green algae, string algae, or blanket weed that floats mat-like at the water's surface. Algae cannot be eliminated entirely, nor should they be. Balance and control are vital to your pond's health and success. Algae-promoting nutrients must be removed faster than they can be produced to maintain this balance. Reduce the number of fish in the pond. Do not overfeed the fish. Skim off uneaten food. Add aquatic plants that use algae as a food source, effectively removing them for you. Add snails and tadpoles that also eat algae. Skim off floating mats of algae whenever they appear. Finally, biological filtration will keep some of the algae growth in check. Rinse or replace filter media regularly for best results.
Summer
If you've done your spring maintenance properly, summer care is relatively easy. Feed your fish every day. Goldfish can go for a week without being fed; they eat algae, mosquitoes, and other water organisms. Trim plants weekly and remove the trimmings so they don't clog the pumps and filters. Test for nitrites and pH weekly as well. On a monthly basis, clean filters and pumps and add mosquito control and plant fertilizer. Reduce feeding as the temperature climbs to 85 degrees F. Add a waterfall, fountain, or aerator to keep the pond cool and oxygenated and to control the formation of algae and the proliferation of mosquitoes. Plants will also help to keep the pond cool and shaded.
Use an automatic feeder if you go away on vacation. You'll still need to have someone check that the pumps and filters are working. Install a skimmer system to help with the filtration. The water garden is at its loveliest in the summer, yet it does not end when summer turns to fall.
Autumn
The water garden has been beautiful, but with cooler temperatures coming, it is important to winterize the pond. Aquatic life takes a rest, and proper maintenance will ensure that they all get through the winter. During the summer, debris has accumulated from leaves, organic matter, and algae. Remove dead leaves with a skim net. Use bacterial cleaning products to reduce sludge buildup. Then use an algae and silt strainer to remove sludge from the bottom.
Trim bog and marsh plants before the frost. Pull out water lilies and trim leaves before they can fall into the pond and rot. Lilies won't survive the winter, so discard them in autumn or bring them inside and store them in peat moss. Place all the potted plants in the deepest water to prevent freezing.
In autumn, change 50% of the water; this can be done in two days. Pump out sludge and water at the same time. Add conditioner and stress coat to the new water. Test for salt and add as needed. Also, add antibacterial medication if any of the fish have been injured during cleanup. Remove 90% of the leaves and silt, but leave a bed of some mud and leaves in which your fish and other aquatic life can hibernate. Cover the pond with black plastic bird netting, which is almost invisible, to keep debris out. Most of your maintenance should be done in the autumn when your fish are at their best.
Winter
When the temperature drops to 65 degrees F, feed your fish with the appropriate seasonal diet: less protein and more carbohydrate. Stop feeding fish altogether when the temperature falls below 42 degrees F. The fish will over-winter in a pond with at least 18 inches of water. If less deep, take the fish out of the pond and relocate them inside, in a kiddie pool or an aquarium, in a cool basement or garage. Provide oxygenation with an aquarium air pump or small fountain. Monitor pH, ammonia, and nitrite levels weekly and change 20% of the water monthly until spring. Feed infrequently or not at all. Cover the pool with bird netting if your fish are jumpers.
By bringing fish and plants inside, another problem may arise: parasite infestation, like ich and flukes, among others. Parasites that attack the gills result in the fish exhibiting breathing problems, flashing, scratching, hyperactivity, and darting. Use an antibacterial medication to get rid of bacterial infections.
For those fish hardy enough to stay in the pond, you won't need filtration at this time, but keep water moving at the surface to provide oxygen. If ice forms, oxygen won't be able to penetrate and toxic gases will be trapped inside. A submerged pump will keep oxygen going and a part of the pond from freezing. Floating pond heaters, air pumps, and diffuser stones also will keep a small area ice-free. If the ice is long-term, melt - don't break - a hole and keep it open. Keep snow off the frozen pond so the de-icing equipment isn't covered. If you've done your winter care properly, you'll be surprised by the new growth that the coming spring has in store for your water garden.