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Why do I Have Foam on the Surface of my Pond?

21st Nov 2019

Your pond is up and running and your fish are feeding heavily in the unusually warm Summer, it’s all going great. I know how it is, everyone that comes round to my house always wants to put some food in for the koi. People just love seeing them feed, especially if yours hand feed like mine!

You can use lots of things as treats for your koi, here are some of the best:

  • Worms
  • Vegetables
  • Fruit – Oranges are a particularly good one as they raise Vitamin C levels
  • Prawns
  • Dried Shrimps

Variety is such a good thing in a koi’s diet, they can become too used to a certain food and that’s not healthy for them. So have a look at the huge range of foods and treats available on our Website.

One of the questions we get asked a lot here at Bradshaws is; ‘I have a lot of foam on the surface of my pond, why is it there and can you give me a miracle treatment to solve the problem?’

The answer:

Pond Pellets, Flakes and Treats are all high in proteins which are perfect for our fast-growing friends, however they are one of the main causes of foam appearing on the surface of a pond. These are called ‘DOC’ dissolved organic compounds - caused by high stocking, no water changes, or over feeding. What happens is that organic material from plants and animals gets broken down into such a small size that it is “dissolved” into the water. Some DOC molecules have a recognisable chemical structure that can easily be defined (such as fats, carbohydrates, and proteins).

Another common cause is using water treatments. Green water and blanket weed treatments will break down plant matter, so always use a sludge buster afterwards! The best way to reduce green water and blanketweed, is more plants and a UVC filter, so make sure your UV bulb is working before putting treatments into your pond!

So back to more basic terms, foam is caused by excessive protein levels in ponds, and can look unsightly especially if you have a waterfall, or oxygenators, as these can sometimes foam up the pond even more!

So in summary, the best way to get rid of or prevent foam is to perform regular Water Changes. I do a water change of around 10-20% per week using an inline dechlorinator, which are amazing bits of kit. They eliminate the guesswork of trying to measure the right quantities of treatments. This is the One I Use (also pictured below).