You have several options. You could go with a firefish goby, any clow goby, a diamond or yellow watchman goby. Or you should check out the royal gramma. You could get a clown (semi-agressive) and an anemone, but i wouldn't put anything else in there but maybe a yellow watchman goby (or other sand sifter/shrimp goby). But you could still stock a few shrimp, blue leg hermit crabs, and snails. I wouldn't recommend keeping any coral unless you have a good light system i.e t-5 actinic and full spectrum bulbs or metal halide bulbs. If this is your first saltwater setup, i would recommend a FOWLR tank. (Fish only with live rock) as coral and invertebrates are much more sensitive to changes in water parameters.
