**Description:** Simple aquatic animals that grow in green, crusty masses on submerged logs and rocks.
**Size:** Masses can range from an inch to over a foot across.
**Identification:** They look like moss but are actually colonial animals. Their green color comes from a symbiotic relationship with algae.
**Behavior:** Filter feeders that strain microscopic organisms from the water. Their presence is an excellent indicator of high water quality.
**Habitat:** Clean, well-oxygenated forest streams and shallower parts of the reservoir.