Need help decorating my fish tank !?

sounds like your filling that tank pretty good, remember they still have to swim around in it :) anyway, I would suggest plastic plants that the fish wont get caught in because they might hurt themselves. the reason I don't get real plants is because they had small bugs in them that passed diseases to my fish. you can decorate your tank with what you want as long as they wont get caught in anything and can swim freely. the stones that you put in the tank should be thoroughly washed before placing them in the tank, some can give off dies into the water. a tank background would be nice but make sure there is enough natural light coming into the tank in the day (you don't want the background to block it all out) and a shipwreck would be nice to finnish off the decor. good luck!