Weird green stuff and plants not living

[Andrew]

I have a 55 gallon tank with a variety of rainbowfish, two plecostamus', an iridescent shark, a few gouramis, and a variety of barbs. Recently we added a whole bunch of live plants to the tank like amazon swords in particular. It seems as though something is wrong because they turn brown in about a week. Also, there is this weird algae stuff that grows on the plants and the fake plants that the plecos dont eat. How can I get rid of it?