About 4 years ago I built a small pond . I had a pond lily in it , which spread like mad , and I always left the leaves to die off and sink . Eventually this pond was infested with duckweed . I hate it . I think it was the reason a lot of the wildlife died. Last year all the water evaporated due to the hot weather. I rescued about a dozen or so tiny frogs . Everything else was dead. In a way I was glad as I now decided to get rid of all the stuff from the bottom , including the lily . Over the winter , the pond has naturally filled back up. Frogs spawned in it earlier this year . Sadly the tadpoles have mostly died due to the pond being pea green soup ish. However , I have noticed that the pond now has quite a few water boatmen. In fact , maybe 20 - 30 baby ones. Where did they come from ? I know the pond is green and cloudy , but ive not seen the parents. Today I have ordered some oxygenating plants to hopefully clear the water for next year.