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.

Prevention

• Regular water changes
• Regular aquarium cleaning
• Avoid overfeeding fish

Regular tank cleaning and water changes is the best preventative measure. Never the less, it is still quite normal to see small amounts of this type of algae. Prompt attention to sudden algae overgrowth growth will prevent more serious problems.