Toxic blue-green algae returns to Austin lakes

Austin officials have detected toxic blue-green algae, also known as cyanobacteria, in Lady Bird Lake and Lake Austin. The algae, which can contain the neurotoxin dihydroanatoxin-a, have been responsible for the deaths of six dogs since 2019. The city is warning lake users to avoid algae, scum, and murky water. Symptoms of algae poisoning in dogs include excessive drooling, vomiting, diarrhea, and more, while humans may experience rashes, irritation, swelling, and other issues. As temperatures rise, more algae growth is expected. The city completed a pilot project in 2025 to treat specific areas with lanthanum-modified bentonite, but will not be treating the lakes this year. Algae info. Report illness.