It’s no secret that lake trips have become a popular vacation destination, but does that mean they are safe to bring your beloved furbaby to? After all, some dogs love swimming so much that you might think they were fish in a past life, however, it’s important to be mindful of safety risks, even for champion swimmers—especially for champion swimmers.
What could be a downfall to them swimming in a lake? Blue-green algae. In fact, it poses dangers to dogs, including neurological, GI issues and in some cases, even death. So far in 2025, Colorado,Florida and Kansas reported blue-algae sightings (among others), and at least one seven-month-old puppy died in Canada less than an hour after swimming in a lake with blue-green algae.
This begs the question: Should you cancel your lake trip due to the dangers of blue-green algae to dogs and would you recognize this deadly water risk? Here’s what vets want you to know.
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What Is Blue-Green Algae?
“Blue-green algae is also known as cyanobacteria,” Dr. Julie Hunt, DVM, a veterinarian contributor for Embrace Pet Insurance reveals. She adds that there are many types of cyanobacteria, but Dr. Hunt notes that some blue-green algae produce toxins known as cyanotoxins.
“Some cyanotoxins can cause neurologic effects, others can affect the liver, and still others can cause negative systemic effects,” she explains. “Cyanobacteria can reproduce rapidly under certain conditions, producing algal blooms that can be dangerous to humans and animals that come into contact with them, if those algae produce cyanotoxins.”
Dr. Silene St. Bernard, DVM, a veterinarian with VCA Animal Hospitals, says you can find these algal blooms in any stagnant water (water that doesn’t move, isn’t cleaned or remains unchanged)—not just lakes. Consider swimming pools and bird baths as potential breeding grounds as well.
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Should You Cancel Your Lake Vacation Because of Blue-Green Algae?
Not necessarily, but veterinarians stress that it’s essential to understand that blue-green algae poses dangers to a dog’s health, including neurological ones and sadly, death. Awareness and mindfulness is key to keeping your furry bff safe.
“If the lake you’re visiting has a history of harmful algal blooms or has an advisory out for harmful algal blooms, then your dog should either be left at home or be kept under the control of a leash when around the water,” Dr. Hunt shares.
If not?
“Then, I don’t think that the dog needs to be left at home and miss out on the fun of a lake trip—just be aware of the signs of algal blooms and go have fun with your dog,” Dr. Hunt says.
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How to Spot Blue-Green Algae
The Environmental Protection Agency advises pet owners to check the water for toxic algae before letting their pets swim. Yet, it’s not always easy to spot it.
“While you can sometimes see the algal growth in or on the water, it is not always visible, nor is it always blue-green in color,” warns Dr. St. Bernard. “It can also be reddish brown and can appear as mats or look like scum on the water.”
Dr. Hunt notes it might look like a…not very aesthetically pleasing art project.
“Some people have compared it to the appearance of spilled paint on the surface of the water,” Dr. Hunt says, adding that this toxic algae can look foamy, appear on the surface of water and smell foul.
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4 Ways to Keep Your Dog Safe From Blue-Green Algae Dangers
You don’t have to skip your lake vacation because of the threat of blue-green algae. Still, blue-green algae contains dangers to dogs, so you’ll want to take precautions to keep your furry friend safe while swimming. Veterinarians shared their top tip.
1. Find Water with Flow
Some dogs have no desire to swim. Others can’t resist making a splash. If the second one sounds like your dog, Dr. St. Bernard suggests finding bodies of water with good flow or in areas with frequent rain. (Rain keeps water moving.)
“Swimming pools that are kept clean are also a great option,” Dr. St. Bernard points out. “Oceans may seem safe, but algal blooms do occur when there is not much.”
2. Look for Warnings
Spotting blue-green algae is hard for the naked, untrained eye. However, Dr. St. Bernard notes that this toxic algae, which poses dangers to dogs, can also affect other mammals. Experts, like municipal workers, in the area may have taken notes and posted warnings.
“Check before you go to see if there are warnings posted in the local news or online for the area,” Dr. St. Bernard says. “If there are algal warnings, then the marinas, canals and other water inlets off the ocean will also be impacted.”
3. Pack and Carry Clean Water
You likely have no intention of drinking lake water. Your dog? You’ll want to ensure they have another way to quench their thirst.
“If you are hiking or traveling with your dog, carry safe, clean water and a water bowl with you so that you have drinking water to provide for your dog, so that they don’t want or need to drink from a source that potentially is contaminated with blue-green algae,” Dr. Hunt says.
4. Leash Your Dog
A lakeside hike may not be the best time for a sniffari, given the dangers of blue-green algae to dogs.
“Consider keeping your dog on a leash when you are near water sources that may be contaminated with blue-green algae so that your dog doesn’t have access to drinking from these water sources,” Dr. Hunt advises. “It only takes a few seconds for your dog to run over and drink from these water sources and ingest toxins.”
What To Do If Your Dog Is Exposed to Blue-Green Algae
If you suspect that your dog has been exposed to blue-green algae after entering the water, it’s vital to act quickly.
“Get them out of the water as soon as possible and rinse and bathe them thoroughly with fresh water so they don’t lick themselves and ingest any more than they may have by swimming,” Dr. St. Bernard emphasizes. “If your dog shows any clinical signs, get them to the veterinarian immediately because these toxins are dangerous.”
You can perform a search for veterinarians in your area if you’re vacationing.
Dr. Hunt reports that the signs of blue-green algae vary by the type of algae, but can include:
muscle tremors or rigidity
Dr. St. Bernard notes that there are no medications specifically designed to eliminate the algae from your dog’s system. However, vets can try to flush it out with IV fluids and provide medications for other symptoms, like vomiting and seizures. Veterinarians emphasize the importance of prompt care to put your dog in the best position to heal.
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Sources:
There’s a toxic blue-green algae bloom at Cherry Creek Reservoir. Denverite.
DOH-Orange Issues Blue Green Algae Health Alert for Lake Olivia (SW. Shore). Florida Health.
Health officials issue advisory for Almy Pond due to blue-green algae bloom. WJAR.
7-month-old puppy becomes sick and dies after swimming in Merritt-area lake. Global News.
This story was originally reported by Parade Pets on Aug 27, 2025, where it first appeared in the Dogs section. Add Parade Pets as a Preferred Source by clicking here.
