Author: Aqua Gardening

The Importance of Oxygen in Ponds

If you have a pond or tank with fish and aquatic plants, you need to ensure that you are maintaining the right oxygen levels. Some people feel that if they have a water feature, pipe or fountain pouring water into a pond, it’s the only aerator that they need. However, that amount of oxygen may not always be sufficient to sustain healthy aquatic life in your pond.

What Happens When the Oxygen Levels Are Too Low?

It is essential that the oxygen level in your pond is just right. For instance, if the level is too low (around 5.0ppm), the growth rate of your fish will be stunted. The fish may also get sick more easily or they may also perish in the water.

If the oxygen level is even lower than that, (eg. 3.0-4.0 ppm), you will notice that the fish pipe/gasp at the surface of the water and they will surely die. You will also notice that the larger fish in your pond die first when the oxygen levels in your pond drop. This is because they need more oxygen just to live.

This creates a domino effect of sorts - when the larger fish die, their bodies start breaking down. This decay process increases the demand of oxygen in the water even further and you will find many more fish dying.

The problem gets aggravated in the summer because water that is warmer carries far less oxygen compared to cold water. Pond oxygen problems get escalated in the summertime as the water is much warmer then.

Algae and other submerged plants add to the problem. They consume oxygen after dark and this can have an impact on the overall oxygen levels too. When the water is warmer, the metabolism of the beneficial bacteria is at heightened levels and they need more oxygen. If the water isn’t aerated well, the growth of these bacteria will be impacted.

Pump Positioning for Greater Oxygenation

In case your pond is more than 15cm in depth, it is crucial that you place your pump at the bottom of your pond. The water at the lower levels in the pond does not have enough oxygen and the pump will help push it up towards the surface for oxygenation. It’s a good idea to invest in a water oxygen-level testing kit to keep track of whether the oxygen levels are at the required levels.

How to Increase the Oxygen Levels in Your Pond or Fish Tank?

If you are serious about maintaining a healthy system with good levels of beneficial bacteria, healthy fish and aquatic plants, it’s important to add an air pump to your pond or fish tank.

Be extra careful in the summer months and keep track of any fish that are dying. This could be an indication of poor oxygen levels in the pond and you should address it without delay. If you find excessive algae growth during the hotter seasons, you might want to clear some of it from the water or add some sucker fish. This will help give the fish more space to move in, and more oxygen to breathe.