Aerating a fish pond


Having enough aeration in a pond is vital for the well-being of fish, as well as the health of the pond water. Bigger fish such as Goldfish and Koi need oxygen-rich water so having the correct amount of aeration for them is essential. There are three signs that will indicate that you don’t have enough aeration. These are:

  1. The fish are constantly gasping at the surface of the pond. Some people can mistake this for the fish just being hungry and throwing food in the pond can only make the situation worse. The fish will be gasping at the area where water is entering the pond, if any.


  1. There will be foul odours such as the smell of rotten eggs, which comes from the anaerobic bacteria that produces Hydrogen Sulfide when it is breaking down decaying organic matter. With the absence of oxygen in the pond the aerobic bacteria cannot survive, which is a lot more efficient in breaking down and doesn’t produce these odours.


  1. There will be an abundance of algae growth. With the anaerobic bacteria slowly doing its job and a great deal of organic matter just sitting in the pond this gives the algae a lot of food to thrive.


To help reduce the amount of decaying matter in the pond you can:

  • Put bird netting over the pond to stop any leaves or clippings from falling in.
  • Use a fish net to scoop out leaves and any uneaten fish food. There are finer fish nets available to better scoop out any fine matter in the bottom of the pond.
  • There are treatments such as EcoFix and Lysofoss available that are designed to eat away at that organic matter. They are treatments that you can use on a regular basis to help keep the pond clean.
  • Using a Pond Vacuum. These are the absolute best way to keep your pond clean.

The best way to increase oxygen in a pond is by having water movement. This can be achieved with a submersible pump or an aerator. There are a number of ways you can increase these levels in your pond while keeping to the style you are looking for. You can:

  • Add a waterfall – This will keep your pond looking natural and won’t stick out as much. There are preformed waterfalls that are easier to add to the pond but they can be quite costly. If you wanted to make a waterfall yourself it may require maintenance in the future if it is not built correctly. We find the Expanding Foam is the best way to build your waterfall.
  • Add a Fountain – These can come in a number of different styles. If you have an existing pump there are kits available that you may be able to adapt to your pump, otherwise the majority of pond pumps come with fountain kits. This is one of the absolute best ways to aerate a pond as the pump will propel the water up and break the surface of the pond water on its decent. If the pond is quite far away from power there are solar options available.
  • Add a water feature – These are ornamental figures such as turtles, venus ladies, column’s etc that can sit inside or outside the pond and spit water back in.
  • Add an Aerator – These come in a wide variety of sizes. They are external pumps that have thin 4mm tubing running from them into the pond with an air stone on the end.
  • Plants – This is a great way to oxygenate and filter your pond. If you are wanting to keep the pond as natural as possible without any use of a pump then it is recommended to have 40-50% of the surface area of the pond covered with plants.

We recommend for all pumps to be going twenty four seven if possible as the lowest point of oxygen in a pond is from 12am to 6am. This is when the fish will need the oxygen the most.

If you need help on finding the best way to oxygenate your pond with the look to suit you, whether it be natural or ornamental, then come see us at 39 Farrall Road in Midvale or give us a call on 9250 6063.