One of the most common questions we get about algae of any kind, concerns green water and whether this very common problem is actually harmful to fish.
It would make sense to say that this issue of clarity in any size of pond is really annoying to the pond’s owner. What may have once been a pristine and clear body of water, sometimes turns into a pea green soup overnight.
Green water in ponds, in case you don’t know, is actually created by very small, single cell algae that multiply out to the point where the water may become tinted slightly to the other end of the spectrum where you can’t see an inch down into the pond.
Like algae algae, these little fellow love sunlight and they derive a lot of energy from photosynthesis. Some of them even rise and fall during a 24 hour cycle. In the morning and throughout the day, they rise to the surface to soak in some rays, and at night they fall back down to the lower parts of the pond.