you can easily get a small school of fish.
here are some choices:
tiger barbs
chery barbs
neons
black neons
glo lites
rasboras
glash fish.......the list goes on on.......i would get around 5 of them. if u go with the smaller ones(neons, glo lite etc) you could get more than 5
as an example for tiger barbs:
5 danios: 2 inches full grown, 2 x 5 = 10
5 cories: 2.5 inches full grow(depends on the type to give a more acurate answer), 2.5 x 5 = 12.5
5 tiger babrs 2.5 inches full grown(some say 3 inches though), 2.5 x 5 = 12.5
4 ghost shrimp: 1.5 inches, 1.5 x 4 = 6
12.5+12.5+10+6= 1.3666666 inches per gal. this should be ok as long as you have good filtration and do regular water changes