How quickly can blue-green algae poisoning affect my dog?

It depends on the type of toxin. Neurotoxins can cause symptoms within 15 minutes to an hour, showing signs like tremors, drooling, and seizures. Hepatotoxins take longer—hours to days—and cause vomiting, diarrhoea, and potential liver failure.

Can I tell if water is safe by looking at it?

No, you can't reliably tell just by looking. Blue-green algae can look like green scum, brown film, wispy clouds, or even an oily sheen—and harmless plants can look suspicious too. Even experts need lab tests to confirm toxins, so treat any questionable water with caution.

What should I do if my dog drinks from a pond with algae?

Get to a vet immediately, even before symptoms appear. Tell them specifically that you suspect blue-green algae exposure. While travelling, try to stop your dog from licking its fur, as contaminated water on the coat can add to the toxic dose.

Dogs on the Hills

Green Scum Might Kill Your Dog

Blue-green algae can appear as floating layers of green, blue-green or brown gunk, and you cannot tell by looking whether it is harmless or toxic. Some blooms produce toxins capable of killing pets, making suspicious water something to avoid rather than investigate.

29 August 20267 min read