Vet Tips
August 1, 2023

Blue-Green Algae and Pets: A Threat by the Water's Edge

Discover the dangers of blue-green algae for pets. Learn how to spot the signs of blue-green algae and how to keep pets safe around water.

Dog playing by a lake

Blue-Green Algae, also called cyanobacteria, can be found in fresh, brackish, or saltwater in almost every state. This algae can usually be found near the water’s edge and has a few different looks. These algae “blooms” occur after little rain and usually during late summer or fall when the water temperature is warmer

There are over 2,000 species of this bacteria, but only 80 produce toxins. However, it is unfortunately impossible to tell the difference between species, so it is important to know where this algae could be lurking. Exposure to toxin producing cyanobacteria can cause serious illness, which, sadly, there is no antidote for currently.

Exposure to Blue Green Algae

The algae blooms are most often found in concentrated “mats” near the shore, which makes them easily accessible to pets and people. Unfortunately it doesn't take much; dogs do not need to ingest the mats to become sick. It can be as little as a mouthful of water or the result of grooming. The bacteria stick to the fur and are ingested as your pet licks and grooms themself.

Photo examples of blue-green algae blooms on water
Photo Credit: Wisconsin Department of Health Services Division of Public Health

If you suspect a body of water has Blue-Green Algae, it is best to stay away from it. Do not take a chance letting your dog swim in this water!

Sign of Blue-Green Algae Toxicity

Signs of Blue-Green toxicity can occur minutes to hours after exposure. Signs include

  • Vomiting
  • Diarrhea, dark tarry stool
  • Weakness
  • Yellowing skin and eyes, known as jaundice
  • Seizures
  • Drooling, and disorientation.

Cyanobacteria toxicity is often fatal as it causes liver failure.

If your dog has been in contact with suspected algae or is showing signs, bathe them immediately (wearing protective gear) and take them to an ER while calling poison control on the way. Keep the reference number ready for when you arrive.  

Safe Swimming Resources

If you want to take your dog swimming make sure to check out your local resources.  

Many local health departments test the water frequently in areas known to have outbreaks. Stay alert and look for signs posted at trailheads or by entrances of lakes for posted warning signs.

You can find detailed info at your state’s department of health and environment.