It looks like you have several algae types occurring. The cause of most algae is too much light, too many nutrients, and not enough CO2
. Try cleaning what you can of the algae off and then reduce your photo period to 6 hours. I should have asked if you have live plants. If you do than just cut the light down to 6 hours a day. If you do not have live plants than you can just leave the lights off for a week or more until the algae goes away. Keep cleaning what you can off of the decor and gravel. You can add some fast growing plants like hornwort or some floating plants to help use up the nutrients so algae has nothing to feed on.
You can spot kill some of the algae with a hydrogen peroxide solution. Get a medicine syringe and a bottle of peroxide from a store. Pull up three cc of peroxide and slowly squirt it over the algae. Turn your filter off for about 15 minutes to give the peroxide time to work. It will usually kill the algae in one treatment. You can do up to three treatments at a time every couple of days or so.
What type of light do you have? If you have high light than you need some CO2
or a supplement like Excel or Metricide 14.