24/07/2026
Great summary on Blue-Green Algae
Blue‑Green Algae: The Summer Hazard Every Dog Owner Should Know About
When the weather warms up, ponds and lakes start looking picture‑perfect — until they suddenly aren’t. Blue‑green algae can appear almost overnight, turning calm water into something that looks harmless but carries real danger for dogs. Every summer, Red Fox Learning sees the same pattern: owners don’t realise how serious it is until a walk turns into an emergency.
Blue‑green algae isn’t actually algae. It’s cyanobacteria, a toxic bacteria that thrives in warm, still water. It can look like green paint, pea soup, brown or blue scum or streaks of foam along the edges. If the water looks off, trust your instincts — and keep your dog out.
Dogs are especially vulnerable because they leap in without hesitation, drink the water, and then lick their fur afterwards. Cyanobacteria produces neurotoxins and hepatotoxins, meaning it can affect the brain and liver. Symptoms can appear fast: vomiting, diarrhoea, drooling, weakness, confusion, seizures or collapse. This is a medical emergency, and there is no antidote — only rapid veterinary treatment.
Spotting it early makes all the difference. Look for warning signs from councils, unusual smells, dead fish or birds, or any water that looks discoloured or scummy. Blooms are most common during warm spells, after heatwaves, and in shallow, still ponds — something Hartlepool and the North East see every summer.
If your dog has been exposed, act immediately: get them away from the water, stop them licking their fur, rinse with clean water if you can, and call your vet. Tell them it’s suspected blue‑green algae so they can prepare.
Blue‑green algae is one of those hazards that’s easy to underestimate because it looks so ordinary. But as we teach in our pet first aid courses, fast recognition and fast action save lives. Share this with fellow dog owners — it’s one of the simplest ways to prevent a tragedy.