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The Florida Department of Health works to protect, promote & improve the health of all people in Florida through integrated state, county, & community efforts.

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Blue Green Algae Information

Environmental Health

  •  239-690-2100
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    239-690-2101
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    2295 Victoria Avenue, #206 

    Fort Myers, FL 33901 

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What is Blue Green Algae?

Blue green algae also known as cyanobacteria are a group of organisms that can live in freshwater, saltwater or brackish water. Large concentrations, called blooms, can change the water color to blue, green, brown, orange or red.  Some cyanobacterial blooms can look like foam, scum, or mats on the surface of fresh water lakes and ponds. As algae in a cyanobacterial bloom die, the water may smell bad.

What causes Blue Green algae?

Blue green algae blooms occur when the algae that are normally present grow in numbers more than normal.  Within a few days, a bloom can cause clear water to become cloudy.  Winds tend to push some floating blooms to the shore where they become more noticeable. Cyanobacterial blooms can form in warm, slow moving waters that are rich in nutrients. Blooms can occur at any time, but most often occur in late summer or early fall.

Where can I check the status of Blue Green algae?

For more information on where to find where blue green algae (cyanobacteria) is located, contact The Florida Department of Environmental Protection (DEP) at 1-855-305-3903 or visit the DEP website

Is Blue Green Algae new?

These kinds of organisms are naturally occurring in Florida’s environment and are also found all over the world.

How long does blue green algae last?  Is blue green algae predictable?

The timing, intensity and duration of a blue-green algae bloom will vary from year to year based on nutrient availability, air and water temperatures, sunlight and wind velocity. Since these factors vary from year to year, blooms cannot be accurately predicted.

Is it safe to swim in water affected by blue green algae?

No, it is important that adults, children and pets avoid recreating in water containing blue-green algae. It is best not to come in to contact with water in areas where you see foam, scum, or mats of algae on the water.

If you come into contact with an algae bloom, wash with soap and water right away.  If you experience an illness, please contact your healthcare provider.

Can blue green algae affect me when I am away from the water?

People can be exposed to blue green algae by inhaling tiny water droplets, mist, or spray from a contaminated body of water. This can occur even if a person does not go into the water.

Are there people who are more sensitive to the toxins caused by blue green algae?

For some people, blue-green algae can cause rashes, stomach cramps, nausea, diarrhea and vomiting. People who are very sensitive to smells can have respiratory irritation. Sometimes, high exposures of toxin can affect the liver and nervous system.

What can I do to lessen the effects of blue green algae?

If you come into contact with an algae bloom, wash with soap and water right away. If you experience an illness, please contact your healthcare provider

Can blue green algae affect pets?

Just like people, pets may be affected by blue green algae.  If your pet swims in water impacted by blue green algae, bathe it as soon as possible. Toxins can accumulate on fur, and if your pet licks themselves after swimming they are liable to ingest the toxins.

If your pet is acting ill after being in or near waters impacted by blue green algae, seek veterinary care immediately.

What agency should I contact to report fish kills or illness associated with blue-green algae?

  • Fish Kill Hotline (Florida Fish & Wildlife Conservation Commission) 1-800-636-0511
  • Human Illness (Florida Poison Control Center) 1-800-222-1222.

Additional information on health issues related to algae