It does look like cyanobacteria.
Phosphates, nitrates and lights are the primary food source.
Try to siphon out as much as you can.
Then take the necessary steps to remove the phosphates and nitrates that are already in your tank.
Also try to minimize introducing additional phosphates into the tank.
RockStacker has got you covered. There are chemical treatments that you can add to the tank for cyano, but I would only use those as a last resort (they can have some negative side effects). Cyano is commonly caused by using tap water, overstocking, overfeeding and insufficient flow (powerheads).