How to reduce water usage in the fish pond

Australia is in the grips of one of the worst droughts in recorded history, and it is up to all of us to use and maintain our water garden / fish pond responsibly in order to minimise water usage all while creating a healthy habitat for fish, plants and local wildlife.   Having an accessible water source in your backyard or balcony, whether it be a dish of water or a fish / frog pond, can be a lifesaver for birds, mammals, reptiles, amphibians and insects that rely upon dwindling freshwater sources as our local water holes, creeks and even rivers dry up.  The outlook is not good for average rainfall to return in the foreseeable future, so it is incumbent on all of us to do our bit to both reduce water usage while making it available to the wildlife that depends upon it.

Drought in Australia

Counter-intuitively, water features can use less water per square metre than many other gardens.  This is because evaporation, soil infiltration and plant transpiration rates are lower in water bodies than in many garden types.  But water gardens can use a lot of water if water-changes are done unnecessarily.

In times of water-abundance, water changes are beneficial to the aquatic environment as they dilute the build-up of nutrients in the pond environment, leading to less algal growth in the pond as well as stress upon the fish.  But nutrient levels can be managed effectively by having a greater understanding of the nutrient cycle within your pond and the garden that surrounds it, without the need for water changes.

drought in Australia

The nutrients that we need to deal with in order to keep the water clean, clear and healthy are ammonia, nitrites, nitrates and phosphates.

Ammonia, nitrites and nitrates are all part of the nitrogen cycle.  In low levels, these chemicals are just a natural part of the pond environment, but if they are allowed to accumulate, then algal blooms can occur and/or you may have health issues with your fish and even fish losses.  Without doing regular water changes, the fish pond relies upon adequate biological filtration and the water plant life within the pond to reduce the levels of all of these potentially harmful chemicals.   So lots of plants, good filtration and oxygenation!  The greater the oxygenation, the harder your good bacteria will work to keep the nitrogenous nutrients low.

You can learn more about this cycle here if you like, but you can look at the diagram below to get the gist!

Nitrogen cycles in ponds

Phosphates are the other nutrient that we need to keep in check.  Phosphates are not harmful to your fish, even in higher concentrations, but is like rocket fuel for algal growth!  Thankfully there are water treatments that bind the phosphates and drop them out of solution, making them unavailable for algal growth. Products such as Aquascape Maintain for ponds, will reduce phosphate levels and increase bacterial growth in the pond

The original source of all of the above nutrients is mainly fish food and leaf material that falls into the pond, so make sure that you:

1) Do not overstock your pond with fish

2) Only feed your fish what they can fully consume within a minute or so

3) Scoop out leaves periodically before they degrade within the pond

4) Reduce feeding in the winter months when fish metabolism slows  (for more information on fish feeding, please read this article)

The only way you can know if you are winning your battle with the above nutrients is to test for them.  So, having a test kit on hand is recommended, or you can take a water sample to a friendly pond shop to get your water tested.  Test your water monthly or whenever you thinking something is not quite right.

We recommend that having a water tank installed on your property is great, if possible.  But in addition to this, the overflow from your water tank can be piped up so that it flows directly to your fish pond.  This will mean that on those rare days that the rain does bucket down, you can save every drop of it as well as giving your pond a guilt-free water change!  The fish pond should be thought of as a water storage device in its own right.  When watering the garden, if you can use water from the pond, your plants will thank you for the additional nutrients.