What do i need for my fish tank?

You'll need something to cover the back of the tank like aquarium background paper or even paint, and enough gravel to cover the bottom of the tank 1" deep. You'll also need some source of light above the tank; use fluorescent lights or LEDs. Don't use plexiglas for the cover, it turns milky white and sags when constantly exposed to water or high humidity. Glass is cheaper anyway; find a glass shop to custom cut a 2-piece lid for you. Take the aquarium and filter to them and show them what you want.