Color: Green

Appearance: Circular, thin, bright green spots that adhere strongly to the surface of the glass and other hard surfaces.

Cause:

• Excess light
• Excess nutrients
  

Green spot is a very common algae that is often seen in home aquaria. A small amount of these types of green algae are normal and expected in any aquarium.

Cure:

• Scrub or scrape off surfaces
  

Spot algae can only be mechanically removed. Sharp objects should not be used in acrylic aquariums. Instead use a plastic razor, cloth pad, or a very gentle scouring pad. On glass tanks, scraping with a razor blade is very effective.