blue green algae dogs

Blue-Green Algae: A Toxic Poison That Lurks In The Water


There may be something hazardous for your pet hiding in your favorite watering hole...

Warmer weather draws us and our dogs to the lake. However, there is a hidden danger lurking in the peaceful waters: blue-green algae. Warmer weather draws out the dangerous cyanobacteria in freshwater, causing blue-green algae blooms to form in both large and small bodies of water, even your backyard pool.

Cyanobacteria have a high toxicity level and can be very dangerous for your pets. Since the bacteria are hard to spot with the naked eye, you will need to take steps to keep your dog safe and ensure that they are only playing in clean water.

What Is Blue-Green Algae?

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Blue-Green algae start to grow when the weather reaches temperatures of 75 degrees or higher, which is why its effects are seen more in the mid-to-late summer. According to the ASPCA, cyanobacteria have a high toxicity level causing poisoning in cats, horses, dogs, birds, fish, and even people. The poisoning is caused by the anatoxins and microcystins that are produced by the bacteria. In addition, the increase in phosphorus and nitrogen in the water helps the bacteria to thrive.

When the algae are forming in the water, it can be challenging to see. Sometimes it can look like a thin film across the top of the water. However, when the algae are in full bloom, it can look like pea soup.

Pet owners need to check the surface of the water before letting their dogs enter the water to swim or drink.

Signs of Blue-Green Algae Poisoning

It is easy for dogs to get blue-green algae poisoning. They do not even have to drink the water and can have an adverse reaction by simply playing in it. However, ingestion does have more severe consequences. If your dog drinks water with toxic blue-green algae, they can have neurologic or liver damage.


If your dog has been in or near water sources that have algal blooms, be sure to look out for toxicity symptoms such as:

  • Panting
  • Seizures
  • Excessive drooling 
  • Respiratory failure
  • Disorientation
  • Vomiting
  • Diarrhea
  • Liver Failure

Other clinical signs of poisoning include things like jaundice, tarry stool, and difficulty breathing. If the toxicity progresses far enough to affect liver function, look for things like excess secretions or salivation, and pale mucous membranes, or blue discoloration of the skin and mucous membranes.

Anatoxins are what cause a neurological reaction. Some neurologic signs to watch out for are muscle tremors, muscle rigidity, and eventually death.

Algae Poisoning Treatment


It is essential to take your pet to the vet before the blue-green algae toxicity progresses too far. Veterinary treatment will be vital to helping them recover, but it only helps if you catch it right away. If the toxicity progresses too far, the only option will be to euthanize the dog.

Some treatments to neutralize the toxin are activated charcoal to absorb the algae and intravenous fluids to rehydrate your dog and help reduce shock and support the function of their organs.

If your dog has seizures, then your vet can administer anti-seizure medication to get them under control. Unfortunately, it can take a long time for dogs to recover, ranging from weeks to months. The dogs that do recover from cyanotoxins will likely have long-lasting effects like liver damage. The dog will likely have to have veterinary support for the remainder of their lives.

Have you ever seen blue-green algae? Let us know on our Wide Open Pets Facebook page. 


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