Blue-green algae is extremely toxic

Q. We have blue-green algae and we understand that it is extremely toxic?


Yes blue-green algae if left untreated can be extremely toxic.

Blue-green algae is a type of bacteria and known as Cyanobacteria. You normally find it on the surface of the water, during the warmer months and in still or slow flowing water.

The majority of blue-green algae produce toxins, and different varieties can produce different levels of toxicity.

How do you know if you have blue-green algae?

Usually, it is bright green or blue in colour, can look like oil on the surface or scum like.

Here are some examples:

If you are unsure, please use our complimentary ID service, take some photos and upload so that one of our team can take a look and get back to you. Click here


When blue-green algae are present it is important to not use the water for recreational activities, keep pets and children away from the water as well as livestock and do not use the water for irrigation.


The only way to treat blue-green algae is with an aquatic algaecide. We recommend Coptrol which is used to treat all types of algae including blue-green algae. For more information on Coptrol please click here.

How do you stop it from returning?

Usually when there is an oversupply of nutrients like phosphorus and nitrogen it is the perfect breeding ground for algal blooms.

  • First you need to reduce the nutrient loading of your water body – look at run off and debris that has settled into your water body.
  • Then attack the muck on the bottom of your water body because as this decomposes it lets off nutrients into the water, which algal blooms love – just use Muck Breaker to break down the muck, please click here
  • Look at aeration, introducing an aeration system into your water body will ensure that you are giving the water body dissolved oxygen and with an aeration fountain you are providing movement through the water body which algal blooms do not like. Click here
  • Aquatic Blue – a pond dye that provides your water body with shade by reducing the amount of sun light, which algal blooms need to survive, please click here
by Aquatic Technologies
If you have any questions regarding looking after your dam or pond and what products are the most suitable for your situation, please read through the helpful articles on our site or feel free to contact our friendly team who can help you maintain proper health in your water body year round.
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