Cyanobacteria blooms are sometimes called blue-green algae. In fact, cyanobacteria can cause blooms in a range of colours, including bright blue, red, brown and green. You can find cyanobactoria in all kinds of bodies of water but is more common for them to grow in shallow, slow moving or still water.
https://www.healthlinkbc.ca/healthlinkbc-files/blue-green-algae