No. It’s best to keep them away.
You may have experienced a beach closure due to an algae bloom in the warm months. It is important for humans to avoid swimming in the water. But is it okay for your pet to still jump in? Usually, the answer is no. It’s best they also avoid the water, especially if you have a smaller dog.
What will happen if my dog swims in the algae?
If your dog jumps in, or drinks some of the bright green water before you can stop them, make sure you wash them off with clean water. Keep a close eye on them for the rest of the day, watching for weakness, vomiting, or other signs that they aren’t feeling well. If they seem unwell, take them to a veterinarian.
Dogs have smaller bodies, so even if they only swallow a little water, they can get sick or even die. Smaller dogs are at higher risk of getting sick because they take in more toxins relative to their body weight. Dogs don’t know the difference between safe and unsafe water, and they often swallow a lot when swimming. It is best to keep them away from the water in general if you see or suspect blue-green algae.
Blue-green algae is a type of bacteria, and can produce dangerous toxins in the water and air.
Blue-green algae is cyanobacteria, and it produces toxins called cyanotoxins. There are several types of cyanotoxins, including neurotoxins, which attack the nervous system. Swallowing cyanotoxins may result in blue-green algae poisoning and can be life-threatening. However, this will only occur if you ingest a ton of toxic lake water. The most likely scenario is that pets and humans who come in contact with an algae bloom or the water near shore may feel sick afterwards.
Algae blooms usually happen in warm environments where there are lots of extra nutrients.
Blue-green algae blooms happen when cyanobacteria grow out of control because there is a lot of sunlight and nutrients in the water. Often, blooms occur in warmer months, when agricultural and yard run-off, warm water, and bright sunny days combine. Fertilizer from lawns or nearby agricultural fields washes into lakes and rivers after it rains. The fertilizer is rich in phosphorus and nitrogen, which causes algae to grow rapidly. When the algae dies, it creates a dead-zone in the water. These dead-zones lack oxygen, killing fish and other wildlife.
What does an algae bloom look like?
Blue-green algae blooms can look different on lakes or slow-moving freshwater. It may look like bright green pea soup. It might look like streaks of green on the surface of the water. It might have small green dots, clumps of greenish scum, or floating dead fish. In bad cases, the water will have a turquoise and green tint, almost like paint was spilled on the lake’s surface. It will probably smell bad.
Bottom line: Algae blooms are very common, especially in freshwater areas that get warm quickly. As the weather warms up, make sure to check with your local health department that the water is safe before you or your pet take a swim.
Further reading:
Wisconsin Department of Health – Blue-Green Algae and Dog Safety
Cornell University College of Veterinary Medicine – Blue-green algae poisoning
