love the rock work, that aquascape is very natural! your off to a good start.
looks like you already have an anemone in there, you might not want to have more than one in such a small tank, they can get nasty with each other. keep an eye on it, they usually like a much more established tank, it will probably need regular spot feeding to stay healthy... he also may be a little bleached, you might want to soak mysis shrimp in selcon for feeding.
what type of lights come with the biocube?