I agree with Ruth, reduce light, feed less and it should go away on it's own. I'll also be the one to give you constructive criticism
Unless you bought your set up used and saved the water and rock etc. you should keep a very close eye on your tank parameters since you already put fish, inverts, and mushrooms in. In the near future you will likely get some 'spikes' that may kill some of your tanks inhabitants.
HTH
Mike