Goby, goby, and gobies. Thats it mostly it haha you can try some of these fish if you like to.
Nano Fish
But thats it. NOTHING else. Inverts if you dont get the wrasse, but if you do, just coral and that ONE fish. Seriously. Try to stay away from the firefish, it is most likely going to jump out if not happy (with that size it probably won't be) Get lots of hiding places for your fish like rocks, live or regular. Caves and holes are perfect. Other than that, get a good secure lid, lighting, and some other sort of wave/current maker (if you are serious about a firefish). Good luck. PLEASE keep us updated