For a five gallon... I have two suggestions.
A larger fish on it's own - i recommend Bettas (Siamese Fighting fish) they're better alone, bright, and great to watch!! (Plus you could have something like a snail or some shrimps kept with it, they prefer them to fish company).
Or a small school of fishes, like some of the active zebra danios.. or some wonderfully beautiful tetras. Good luck.
And congratualtions on the new tank.