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Are you making this common pond mistake?

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Photo by Quinn Dombrowski.

I always thought that my pond would get plenty of oxygen between the waterfall, the plants and the surface of my pond. Wrong!

  • Oxygen can only be “absorbed” into your water where it comes in contact with air. Oxygen is only absorbed at the surface level, this doesn’t help the levels in the deeper water.
  • Air is only about 20% oxygen.
  • Plants should cover no more than 50-60% of your pond surface.

We all know that our fish need dissolved oxygen to breath, but that is only one of the reasons that our ponds need it. Aerobic bacteria require oxygen to breakdown toxic substances (like ammonia) in our pond water. The more organic waste that  is in the water, the more the bacteria use oxygen. Low oxygen levels will suppress our “beneficial” bacteria, making it difficult or impossible for it to do it’s job.


Photo by Peter Shanks.

Submerged plants can both help and hurt our ponds oxygen levels. During the day they produce oxygen, but at night they consume the oxygen and compete with the fish for the limited supply that is in the water. That’s why your fish sometimes die in the early morning.

Mid to late summer can be extra hard on the pond’s oxygen levels because of the increased water temperature, the plants have grown, and possibly more fish. All of these things can drop the oxygen levels to the point where there are serious problems with your pond and fish.

The fastest and possibly the most efficient way to add the needed oxygen to your pond is to add an aerator.  In addition to adding oxygen it also will create vertical water movement. This brings the stagnant cooler water to the surface so it can be exposed to air and sunlight. Some people like to run their aerators at night when their ponds need it most, and have it off in the day (although it only costs about $1.00 to run the Aquascape aerator per month). Other ways to help your oxygen level are:
  • Don’t over stock your pond.  Recommended – one inch of fish per one square foot of surface area.
  • Reduce the amount you are feeding your fish.  Try to feed in the morning or late evening when temps are lower.
  • Do partial water changes to lower water temperatures. Warmer water can hold less oxygen.

Anyone else using an aerator?  Tell us about your experience in the comments.

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