Ever heard of the nasty Blue Green Algae and how poisonous it can be to us dogs?


Its not easy being a black coated mountain dog when the weather is getting warmer. Especially not when you have so many canine friends to play with and dog toys to chase. In fact, unless you get  a short haircut like my blogging friend over at a view from the furry side’  you have to resort to diving into the nearest pond, brook, river or mud puddle.

As you know that’s never been a problem for me at all, in fact I love swimming, but then I ran into a warning sign in Richmond Park for something the humans called ‘blue green algae’. I didn’t know there could be anything dangerous for us dogs in the water and it kind of spooked me into reading up about it. I was visualizing this algae stuff to look like nasty little blue-green crocodiles with sharp teeth, lurking under the surface of the water waiting for a fat little puppy (dinner) to swim by.

What is Toxic Blue Green Algae?

Turns out the blue green algae doesn’t actually chase or stalk innocent dogs. Blue green algae is actually a nasty, toxic type of bacteria called Cyanobacteria that lives in water such as lakes and ponds and can be deadly poisonous to dogs in much nastier ways than by simply biting them.

When and Where is Blue Green Algae poisonous to dogs?

The toxic blue green algae is sneaky and exists in water all year round biding their time. But it is only when there’s been a long period of warm sunny days that they thrive to a dangerous degree. The blue green algae blooms (that means it reproduces very quickly) especially in shallow, nutrient rich bodies of water such as ponds and lakes where dogs and puppies like myself love to go swimming. In these warm conditions, which usually happens in late summer, the algae can suddenly bloom and thereby produce a powerful toxin which is one of the most powerful natural poisons known. It is very scary stuff.


Play in running water such as brooks or rivers to avoid blue green alage

What happens if a dog drinks water contaminated with Blue Green Algae?

Listen up my dog friends out there – this is important. If you think you have been swimming in and drinking water with blue green algae in it, you only have four to five hours to live. You could get really ill within as little as twenty minutes so make sure your human takes you to the vet straight away. The symptoms to look out for is acute salivation and pale gums.

How to swim safely and avoiding Blue Green Algae

The very safest option is of course to stay well clear of all water like my blog buddy Alfie Dog – but not all of us are that naturally distrustful of all waters. Some of the toxic blue green algae can look like foam, scum or mats on the surface of the water when its blooming – but to make it extra tricky some of them are not visible or come in different colours like blue, green or brown. You can’t use your nose to smell the algae either as not all the bad algae give off any odor. Its tricky business.

One of the many ways blue green algae can look in the water

One of the many ways blue green algae can look in the water (thanks Inga for supplying the photo)

The algae can of course grow in any type of water but some are safer to swim in than others. So, the trick seem to be to avoid stagnant ponds, puddles and lakes when the weather has been hot for a while and instead cool down in the sea or a river where the water is constantly moving and generally cooler. Always swim with a little food in your belly as a full stomach buys you more time if you are unlucky enough to drink toxic water – and more than anything tell your humans to keep their eyes open and look out for any symptoms you might show.

Has anyone ever seen this nasty algae stuff or know any tricks how to spot it? Please share your experiences in the comments section below.


Could there be blue green algae in the water?



  1. Inga says

    Hi Alfie, yes I’ve heard of this ugly stuff, in fact we once saw it in the water when we were sailing….
    This is what it looked like (I hope you can ‘translate’ this into a real photo? I don’t know how to add a photo to a blog….!):


    I didn’t know that it can make dogs so very sick so quickly, please be very careful! And if you go swim in a river, beware of the current?!

  2. Jecinta says

    Hay my name jecinta my 6 month year old puppy milo went swiming in blue green aglea yesterday I didn’t no it was that till today he seem to be fine what should I do I don’t wont to lose him the vets are closed so I can’t even go in and get a cheak up and see if he ok when will I no if he is in trouble

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