Fish Ponds: Spring Time Maintenance

Now is the time to start cleaning the koi, goldfish, and other ponds. Ponds need to be cleaned at least annually. If the pond has any debris on the bottom, the water in your pond will have trouble staying clear for your enjoyment. Algae feed on the organic decaying matter in the pond. As the weather and water warms up, the algae begin to feed on the organic  matter and a “bloom” will occur that will turn the water cloudy.

Another reason to clean the ponds is to get rid of disease carrying parasites that live in the decaying matter. These parasites seek out the koi and other fish and can cause them to become sick.

Several methods are available to clean your pond. If the pond isn’t too large and/or dirty, it can be cleaned using a net to muck the stuff on the bottom. I have my ponds cleaned by an IPPCA professional at least once every other year. My koi pond has three “waterfalls” and contains about 9800 gallons of water. (I would have added a photograph but my digital camera decided to die on me. Sorry!)

I recommend that you select pond professional that is a member of IPPCA (The International Professional Pond Contractors Association). It is the not-for-profit trade association whose goal is to ensure that high quality standards are met within the pond and waterscape industry.

For who like to go it alone, put on your boots and gather some old towels or rags, a garden hose, a water pump, a couple of 25 gallon tubs to hold the fish, an aeration pump for the tubs with fish (not necessary if you work quick), a wet-dry vacuum cleaner from the hubby’s workshop, some buckets, and at least one net.

You can use a garden hose to siphon the water out of the pond. I use one of my water pumps to get most of the water out of my three ponds. The nutrient rich water from my pump discharges into a future “bog garden.” (I plan to build it some day.) You can also use this water on the lawn and flowerbeds. As the water drains from the ponds, gather up the pond plants and set them in buckets, along with some pond water. Place them in a shady area. Some of the water from the pond also should be pumped into the holding tubs set aside for the fish.

When the water level in the pond drops to about 6 inches, put your boots on, climb in, and net out the fish. The first time I cleaned my pond, I tried to catch the koi using a cast net with a full pond. I wasn’t very successful but did manage to fall into the pond, which the neighborhood kids thought hilarious.

Gently put the fish in the holding tubs that are about ¾ full of pond water. I use 25-gallon plastic tubs with lips that can be used as handles. It is nice if you have an air pump available to provide some aeration for the fish in the tubs but it is not necessary. You can add a product called “stress coat” to the tub’s water to ease the stress on the koi. Stress Coat does remove the chlorine and it also removes hard metals and adds a protective coating to your fish. Every time you touch your fish, with your hand, net or anything else, the fish will loose it’s protective coating. The fish will then be very susceptible to different illnesses and diseases such as different bacterial infections such as fin rot. If you have koi,
put some kind of cover over the tubs since they have a tendency to “crawl” out of the tubs.

Finishes draining the pond after the koi and other fish have been removed. I use my Wet/Dry Shop-Vac at this point. The muck on the pond’s bottom is a good fertilizer for the garden.

Now is a good time to check the main water-circulating pump to make sure it is working properly. I have a skimmer system that acts as the filtration system. I clean the filtration members and flush out the line that circulates the water from the lower pond to the upper waterfalls.

Start refilling the pond with tap water by gently rinsing down the sides of the pond with a garden hose. What every you do, don’t try to scrub it clean. The material on the pond’s sides contains beneficial bacteria that aid in balancing the pH of the pond.

Tap water is chlorinated so be sure to use a product called “Pond Start” or something similar to rid the water of chlorine and chloramines that can be deadly to the fish. Check the pH and temperature of the fresh water to ensure that it is almost the same as the pond water in the holding tubs. If they are not the same, add a little of the fresh water to the water in the holding tubs. This will help acclimate the fish to the new water conditions.

The reason I use a pond professional is that they will check the fish for parasites and sores. If they find any that have parasites, they will quarantine them in a separate tank. The professional will treat the sick fish in the quarantine tank.

When a about a foot of fresh, de-chlorinated water in the pond, pour the fish and water from the holding tubs back into the pond. This water helps to inoculate your pond with beneficial bacteria. Return the fish back into their clean home as soon as possible to prevent over-stressing them.

While the pond is continuing to fill, clean up the plants and return them to the pond. I add “Aqua One” or “OneFix” once a year to the water (each cost about $40-50). These are all-natural microbial water treatment that digests suspended organic matter and prevents additional accumulation by removing the nutrients released from decaying algae. Basically, it helps keep the pond clear and free from all forms of algae. I have had little success with barley straw but you can give it a try.

A Bit of Dirt – Spring 2010

The full pdf copy of this edition is available here.


I’m writing this in early February and have survived the coldest snap in Georgia in 30 years. Hopefully all of your plants will have survived. I have been going through my spring gardening catalogs looking for seeds to start in the coming  months. I have decided try to start some Cherokee purple, Rainbow Yellow, and Rutgers (red) tomatoes.

The 2010 Georgia Master Gardeners will have completed their classes by the time you read this. Let’s encourage the new interns to complete their volunteer hours, both in and outside the extension office.

The Gwinnett County Master Gardener’s Plant Sale will be on May 7th this year. Volunteering for this and other activities is a wonderful way to meet and socialize with other Gwinnett County Master Gardeners. On May 6th we will need volunteer to assist setting up the tents, tables, placing the plants in their proper location and watering the plants that need it. On May 7th we will need volunteers to discuss different plants with potential customers, sell plants, and carry them to the  customer’s vehicle. Prior to the plant sale on May 7th, I hope many of you will be digging and repotting your pass-along plants for the plant sale.

Spring is one very busy time planting and caring for your gardeners. Hopefully, you will reserve some of your valuable time for other activities that are sponsored by the GCMG Association. We always need volunteers to: keep presentable the gardens at the Bethesda Senior Center (we get the meeting room for free if we maintain the gardens); participate in Plant Clinics; help out at the various Home and Garden shows; participate in the annual Plant Sale; assist planting, maintaining, and harvesting the vegetable garden at McDaniel Farm; work at the Vines Gardens; answer the phone at the Master  Gardeners Desk and perform other duties in the Gwinnett County Extension office.

Thanks for keeping up the good work done by the Gwinnett County Master Gardeners.

Other articles in this issue:
Fish Ponds: Spring Time Maintenance – By Dan Willis