I see what looks like a curtain on the left of the picture..
Does the aquarium get any natural light?
Also, are you adding anything to the aquarium to give plants nutrition.
Algae looks like it might be diatoms, if so it should go away on its own over time once there is not enough to feed it
Water changes can help, as will increasing the number of plants you have, especially floating, rhizome or stem plants.i
Not sure I want to suggest livestock to take care of the issue, unless you are planning to add them already.
Does the aquarium get any natural light?
Also, are you adding anything to the aquarium to give plants nutrition.
Algae looks like it might be diatoms, if so it should go away on its own over time once there is not enough to feed it
Water changes can help, as will increasing the number of plants you have, especially floating, rhizome or stem plants.i
Not sure I want to suggest livestock to take care of the issue, unless you are planning to add them already.