wimming, boating, and exploring near the water are popular activities for many South Florida dog owners. While most outings are uneventful, lakes, ponds, canals, and other bodies of water can occasionally contain a potentially serious hazard known as blue-green algae.

Despite the name, blue-green algae is actually a type of bacteria called cyanobacteria. Certain cyanobacteria can produce powerful toxins capable of making animals seriously ill.

Dogs can be particularly vulnerable because they may drink from unfamiliar water sources, swallow water while swimming, or lick contaminated water and material from their coats after leaving the water.

What Does Blue-Green Algae Look Like?

Potential cyanobacterial blooms can vary considerably in appearance.

Contaminated water may appear green, blue-green, brown, or rusty in color. Some blooms resemble paint or scum floating across the surface, while others may collect into mats or streaks near the shoreline.

It is not possible to reliably determine whether water contains dangerous toxins simply by looking at it.

For that reason, pet owners should keep dogs away from water that appears discolored, stagnant, unusually cloudy, or covered in algae or surface material.

Pay attention to posted warnings around lakes, ponds, parks, and recreational waterways.

How Are Dogs Exposed?

Dogs may be exposed by drinking contaminated water or swallowing it while swimming.

Exposure can also occur without intentionally drinking from the water. A dog that swims through contaminated water may later ingest toxins while licking and grooming its wet coat or paws.

This is one reason pet owners should not allow dogs to enter questionable water even if the dog does not normally drink while swimming.

Why Can Blue-Green Algae Be Dangerous?

Different cyanobacteria can produce different toxins.

Some primarily affect the liver, while others can interfere with the nervous system. Certain exposures may also cause skin irritation.

The severity of illness can depend on the type and amount of toxin involved, but serious cyanobacterial poisoning can progress quickly. Suspected exposure should therefore be treated as an urgent veterinary situation rather than waiting to see whether symptoms develop.

Signs of Blue-Green Algae Poisoning in Dogs

Symptoms can vary depending on the toxin involved and the degree of exposure.

Potential warning signs can include:

• Vomiting or diarrhea
• Excessive drooling
• Weakness
• Difficulty walking
• Tremors
• Seizures
• Difficulty breathing
• Collapse
• Changes in gum or skin color
• Sudden severe illness after swimming or drinking from an outdoor water source

Any rapid change in a dog’s condition after exposure to a lake, pond, canal, or other natural body of water warrants immediate attention.

What Should You Do After a Suspected Exposure?

Remove your dog from the water immediately and prevent them from licking their coat.

If possible, rinse your dog’s fur thoroughly with clean, fresh water while protecting yourself from contact with potentially contaminated water.

Contact an emergency veterinarian immediately and explain where the exposure occurred and what you observed.

Do not wait for obvious signs of poisoning before seeking guidance. The absence of immediate symptoms does not necessarily mean an exposure was harmless.

If local authorities have issued an advisory about a particular body of water, provide that information to your veterinarian when possible.

How to Reduce Your Dog’s Risk

The easiest way to prevent blue-green algae poisoning is to avoid questionable water.

Do not allow your dog to swim in or drink from water that has visible algae, surface scum, unusual coloration, or a foul smell. Follow local advisories and posted signs at parks, lakes, and recreational areas.

Bring clean drinking water whenever you take your dog hiking, boating, walking near waterways, or visiting outdoor recreation areas. Providing an easy alternative can reduce the temptation to drink from a pond or lake.

After swimming in safe recreational water, rinsing your dog with fresh water is also a good habit.

When Exposure Becomes a Veterinary Emergency

Possible toxin exposure should be taken seriously, especially when a dog suddenly develops vomiting, weakness, tremors, difficulty breathing, seizures, collapse, or other neurological symptoms.

Prompt veterinary evaluation gives your pet the best opportunity to receive appropriate supportive care and treatment.

Miami Veterinary Specialists provides emergency veterinary care for pets experiencing poisoning, sudden illness, neurological symptoms, breathing difficulties, and other urgent conditions. If you believe your dog has been exposed to blue-green algae or another toxin, seek veterinary assistance immediately.