What is this brown growth on aquarium decorations/pebbles?
its brown algae aka diatoms. Its all part of the cycle. I am currently having this problem with my 10g tank. Just take out all your decor and clean it with warm water, and rub it off or you can just wait it out . I would get a algae eater or a bottom feeder. I just have a black mystery snail to help eat the extra food and diatoms. The diatoms are not bad they will go away eventually just keep it clean. Also I would sypen your tank too with a small sypen to get rid of all the food also a scrubber for the sides of your tank. I am not sure about the green I think that is bad but i am not sure.
