id this carpet

[craig_will2513]

hi can anyone tell me what this is. its in a fresh water tropical tank. its like a carpet of dark green stuff on the sandbed. it looks like mould growing.. here is a pic

 

[severum mama]

Looks like it is cyanobacteria.

 

[craig_will2513]

ok so is that good or bad and how do i get rid of it

 

[severum mama]

This link should give you more info. It's bad.
FAQs on Freshwater Blue Green Algae (BGA) and Their Control