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Blue-Green Algae in Water – Not Safe for Dogs or People

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Updated: September 24, 2020

Avoid Water That Looks Like This

For many dogs, summer often means swimming in lakes, rivers, or ponds. Along with the standard water safety steps (close observation, doggie PFDs, etc) and post-swimming ear cleaning to avoid ear irritation and infections, there’s something else you need to be aware of when you take your dogs swimming (or hiking, or camping near water) … blue-green algae. 

These dangerous algal blooms are most common during periods of high heat.

Read along and tune in to this episode of the Paws & Play podcast to hear Dr. J talk about the dangers of blue-green algae:

Dogs that drink water containing blue-green algae, or that groom the algae off their coat after swimming in such water, can exhibit a range of signs, including:swamp-water-algae


  • Uncoordinated walking (“Ataxia”)
  • Drooling
  • Vomiting
  • Diarrhea
  • Collapse
  • Seizures

If you’re noticing these signs in your dog, at any time, they need to be seen by a veterinarian right away. These are very serious signs indeed, and may well indicate liver failure from blue-green algae exposure.

Here’s more information on blue-green algae in dogs.

Danger for dogs and people – lurking in ponds and lakes

Oh, and be aware, these algae aren’t just a problem for your pets — they can cause illness in children and adults, too! To find out if there are any blue-green algae warnings in your state, just google “blue green algae (insert your state)” or check out these state-by-state resources: interactive map of state's blue-green algae labs and monitoring and state-by-state harmful algal bloom monitoring resources.

Using Technology to Combat Blue Green Algal Blooms: Here's a great tool to help you and your pets (and other family members), as well as other people and their pets and families. Check out and download the bloomWatch app (available for both iOS and Android) to learn more about blue green algae and to help pet owners, scientists, and others find and monitor these dangerous blooms. Citizen science at its best, and working for everyone!

Here are some really incredible photos of blue green algal blooms courtesy of the USEPA and Cyanobacteria Monitoring Collaborative:

2020 JUL 16 Great Herring Pond MA - 1st documented bloom event - Photo Evie Saunders pic 1Blue Green Algae from USEPAMonponsett Pond-Ted broderick-Halifax-MAJon Samuelson Province Lake NH 20171116_073326

You can also follow the social media feeds of CyanoTracker, a citizen science program out of University of Georgia also focused on educating about, tracking, and combating blue green algae. Here's CyanoTracker on Twitter, and CyanoTracker on Facebook.

For more water-related hazards, check out our Dog Swimming: Safety in Rivers, Lakes, and Oceans article.



Topics: Swimming, Dogs Outdoors

Please do not ask emergency or other specific medical questions about your pets in the blog comments. As an online informational resource, Preventive Vet is unable to and does not provide specific medical advice or counseling. A thorough physical exam, patient history, and an established veterinary-patient-client relationship is required to provide specific medical advice. If you are worried that your pet is having an emergency or if you have specific medical questions related to your pet’s current or chronic medical conditions, please contact or visit your veterinarian, an animal-specific poison control hotline, or your local emergency veterinary care center.

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