Loretta - we had Azolla just show up a few years ago along the shoreline of one of our ponds. The plant is small - about 1/4" across. We had no idea what it was, so we left it. When we returned to our property two weeks later, this half-acre pond was completely covered. There was not 1" of water showing. I thought it was duckweed at first glance, but it was the Azolla. It had taken over our pond. We tried to "corral" it to remove it, but the plants were so small they could not be contained. It was a nightmare getting rid of it. I would RUN from this plant!