Stay small. With an 8 you are probably only going to be able to get 1 fish or two small fish. Here is a list of fish that you might consider. Firefish, Clown Gobies, Cardinals, Clowns (only certain types though), sixline wrasse, certain gobies, damsels.
Remember that being on top of your game is crucial with a small tank. I would go with probably 1 clown fish and maybe a clown or neon goby.