How to clean your water pond

How to clean your water pond

As reports come in from Ponders, several people lost some of their larger fish during this long, harsh winter. Many fish died because the ponds froze over and they suffocated to death. With hopes that spring is finally here and the memories of snow behind us, it is time to open our ponds and prepare them for warmer weather.

As the days get longer and the sun warms the air we begin to see activity in our ponds. The fish become more active and our plants emerge from their dormancy. We should begin to see new growth on plants such as marsh marigolds. I have also seen little leaves forming on my hardy water lilies and water irises rising up above the water reaching for the sun.

It’s time to return your pumps to the water after careful inspection of them and your hoses. You can give your biological filters a spring boost by inoculating them with beneficial bacteria available from garden suppliers. Many people have asked me what I use. Even those I do not like to endorse any business or product, this is a product that is highly used by many Ponders. I use a product called Microbe-Lift. This is not a chemical. It is harmless to humans, animals, fish and plants. Microbe-Lift helps to jump-start your pond and maintains a healthy immune system for your fish.

Make sure you are using the correct Microbe-lift for your water temperature. More information can be found on their website at: You can test the water to ensure that ammonia has not built up over the winter months. If you have high levels of ammonia, a 25% water exchange at this time should reduce the risk to your fish. If you have chlorine in the water, you will need to treat it. Be patient if you notice string algae or green water. Once your pond has established a balance this will disappear.

This is also the time to remove your plants and trim or pinch the old growth and all yellowing leaves off. Divide and repot these plants. Give tadpoles, dragonfly larvae and other pond inhabitant time to escape before placing the trimmings on a compost pile. You can fertilize your plants at this time with fish-safe fertilizer pellets to help give the plants a jump-start on the season.

While you are in the pond removing your plants, this is also the time to remove all leaves and debris that may have blown in during the winter. I use my fine-mesh, long-handled swimming pool skimmer net for this job. The removal of this debris will remove potential sources of ammonia, nitrites and nitrates from your water, which is also toxic to fish. Place your plants at their appropriate depths or set them in shallow water to encourage quicker growth and then place them at the depth you want them to be.

My fish (which happens to be Koi) are coming up to the surface looking for food every time I walk out there. You should not feed your fish food until the water temperature reaches 50 degrees F. Someone forgot to tell the fish this. I like to start them out with something like plain ole Cheerios or something that can be easily digested. Wheat-germ-based floating pellets are a good source of food for your fish at this time. Feed them in the morning so that they have ample time to digest their food before the night turns cool. Keep a watch for parasites and diseases in your fish.

Enjoy the spring weather and kiss winter goodbye.


Jennings (pond Lady) President,
Mid-Michigan Pond & Water Garden Club
Advanced MSU Master Gardener


How to Choose a Pond Site
Designing a Pond
Edging for a Pond
Spring Cleanup
Summer Cleanup
Water Gardens

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