Why is blue‑green algae dangerous to dogs?
Blue‑green algae, also known as cyanobacteria, can gather on the surface of water and form a visible layer. It may look like blue‑green scum, pea‑soup water, green flakes, greenish clumps, or even brown specks.
When these algae bloom, they can produce highly toxic substances that prevent a dog’s liver from functioning properly. Not every bloom is dangerous, but there is no safe way to tell the difference just by looking.
Sadly, poisoning from toxic blue‑green algae often leads to fatal liver failure.
Symptoms can resemble many other, less serious illnesses, but if your dog shows any signs of being unwell after swimming or drinking from outdoor water sources, contact your vet immediately.