Blue-Green Algae

What You Need to Know About Blue-Green Algae

Pictured: Beware of slimy blue-green algae
Source: Channel 6 News

Recently there have been reports of pets dying after days spent swimming in bodies of freshwater. In North Carolina, a lady lost all three of her dogs after a play date in a pond. In Texas, four dogs died after going for a swim and even a Georgia police dog is believed to have suffered the same fate after cooling off in a pond. Many of them suffered seizures and died shortly after exiting the water. These bodies of water have all been found to be contaminated with blue-green algae.

So, what is it?
You might be surprised to find out blue-green algae is not really your average algae. Blue-green algae is actually a cyanobacteria, a toxic phylum of bacteria that contain chlorophyll. Their chlorophyll gives them the appearance of normal algae. They are the only photosynthetic prokaryotes with the ability to produce oxygen and in doing so can produce Harmful Algal Blooms (HABs). Not all of them bloom, but unfortunately when they do they are much more dangerous.

How did it get here?
Blue-green algae has a tendency to grow rapidly when bodies of water are subject to extreme heat and high levels of phosphorus and nitrogen. The levels of phosphorus and nitrogen build up in the water over time from a variety of pollutants such as fertilizer runoff, farm animal waste, septic tank overflows, etc. The excessive richness of nutrients in a lake or other body of water results in a dense growth of plant life.

Pictured: Blue-green Algae Source: Pet Poison Helpline

How serious is it?
Blue-green algae are harmful to both humans and animals. Dogs are more vulnerable as they have a tendency to ingest more water when they go for a swim. If a dog is exposed to contaminated water for more than 5-10 minutes it can definitely be fatal. They will likely show symptoms of nausea, diarrhea, vomiting, drooling, neurological signs like weakness, disorientation, confusion, seizures or respiratory difficulty. If not fatal, it can cause long-term health problems like liver damage and cause severe irritation to the skin resulting in fur loss.

What can I do?
The best way to protect your pet is to avoid bodies of water that are cloudy or have a green film on the surface. The blue-green algae can look like green flakes, greenish bundles or brown dots, blue-green scum on the surface of the water and sometimes foam. It often will concentrate along the shoreline in areas where pets tend to play.

Pay attention to warning signs posted at the beach and lakes. Keep your dogs leashed around bodies of water, especially if the water appears dirty, foamy or green in color. Refrain from letting your dog drink out of ponds or lakes. Be aware that toxins are not always visible. Even if your dog appears clean, be sure to give them a good rinse after they’ve been swimming so they don’t have the chance to ingest the harmful bacteria. Head to your veterinary hospital immediately if your dog begins showing any symptoms of toxicity.

For more information please visit




Make a difference in the lives of animals.

Give with Confidence

At HSNEGA, we want to remember the amazing rescues that come to stay with us. All of the animals pictured on this site have been with us at some point. Some have already found their forever homes, but some may still be here at HSNEGA! The Humane Society of Northeast Georgia is a 501(c) (3) non-profit organization (Federal Tax ID #58-0678817) and has received top recognition from the following charity rating organizations:

Best of Georgia, GreatNonProfit & GuideStar Seals