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Blue-Green Algae: A Lurking Danger to Pets

June 15, 2021

Have you ever heard of cyanobacteria? You may know it by its common name: blue-green algae. This is an extremely dangerous algae that typically lives in warm, nutrient-rich water. Cyanobacteria can make both people and pets very sick ,and can even be fatal. The algae can grow rapidly, or bloom, under the right conditions. Unfortunately, these blooms are becoming much more common. A veterinarian discusses cyanobacteria in this article.

 Warning Signs

Blue-green algae blooms usually occur in summer and early fall, or any time the water temperature goes over 23C. Many local authorities and newscasts will alert people when a body of water has been contaminated, and some will post signs. However, it’s easy to miss these updates. This is definitely something you want to check before you take your dog swimming!


As mentioned above, blue-green algae is extremely toxic. You don’t even have to drink any contaminated water to get sick: you can ingest it through skin contact or by breathing in water droplets or vapors. This can happen when people go swimming, boating, or tubing in affected lakes. Cyanobacteria can also stick to pets’ fur, where they can later lick it off.


Blue-green algae actually looks more green than blue: it typically looks like pea soup or green paint. It can also cause a sort of sulfuric, swampy odor. However, you can’t judge by appearance alone. Smaller blooms might not affect the look (or smell) of a lake or pond very much, but they’re just as dangerous. Err on the side of caution here: if in doubt, just stay out!


Blue-green algae can make any pet sick, and it is also a threat to wildlife. As far as pets go, dogs are particularly at risk, especially those that love to swim or play in water. Blue-green algae can cause very serious neurological problems and/or liver failure, and can be fatal. Warning signs include respiratory problems, panting, vomiting, diarrhea, dizziness/disorientation, seizures, and excessive drooling. If your furry buddy shows any of these warning signs, call your veterinarian immediately.


When it comes to pet care, prevention is always worth much more than cure. Be very careful when choosing Fido’s swimming holes. Finally, don’t let your pooch drink from lakes or ponds, especially ones with blue-green scum. 

Do you have questions about pet care? Contact us, your animal clinic, today!