The Blue-Green Aquarium Algae is often referred to as slime or smear algae, but is not actually an algae at all; it is a cyanobacteria. It spreads extremely quickly and can cause damage beyond repair.
Excesses of nitrates and phosphates in the aquarium cause it, and you will probably need to use special water treatments to remove the nutrients, which in turn, will remove this aquarium algae.
Excess light, high levels of organic wastes, anaerobic conditions.
Do more water changes, avoid overfeeding the fish and do not use excess light.
How to remove
Reduce the light intensity, do more water changes, clean the tank.