Waterscapes 101 Knowledge Base

Algae Facts

Algae is a group of microoganisms that make their way into water bodies of all sizes. Algae cells can be carried to a water body via bird, land animal, boat, fishing gear, and even the air! The proliferation of algae depends on nutrients and sunlight to grow. 

Algae forms fall into 3 groups:

  • Filamentous Algae
  • Planktonic Algae
  • Chara

Filamentous Algae

Filamentous algae is commonly referred to as string algae. String algae begins growth at the bottom of the pond. There are many species of filamentous algae so not all algae blooms will look the same.

String algae can look like green mossy mats, or even long hair-like strands. The consistency of this growth can vary from slimy, to a cotton consistency.

As string algae matures it eventually releases to the surface of the pond. It becomes buoyant from the oxygen it is producing.


Planktonic Algae

Planktonic algae is commonly referred to as green water algae. This is microscopic algae that is suspended in the water column. Planktonic algae is a sign of a serious imbalance in a pond which can cause harm to fish.

Algae Blooms can lead to fish kills

Like all forms of algae, planktonic blooms produce oxygen during the day. At night, algae consumes oxygen. A heavy planktonic bloom can result in a fish kill from oxygen uptake at night. These kills can also occur when there are consecutive overcast days. When sunlight is blocked, the planktonic algae consumes oxygen during the day instead of producing it.



Chara is commonly misclassified as a submerged weed. The “leaves” around the stems are similar to coontail or spiny leaf naiad. Chara is actually a form of algae. There are a few distinct characteristics to look for. Chara has a gritty calcified outer coating. It also has a skunk like odor. Chara is typically found in hard water. There is no root system. Just like string algae chara will start growth at the bottom of the pond and they release to the surface in mats. 


Algae Control Treatments

Waterscapes 101

The knowledge Base for Pond and Lake Management