There are bunches of fish that will be perfectly happy in a 14--particularly if you're planting it. Smaller pencils, many of the wild bettas/licorice gouramies, the microrasboras, badis badis, and of course all of the different shrimps would be perfect for a 14. However, each other those animals have specific care needs, and not all are necessarily well suited for a new aquariast. Small tanks are great, but they do require more attention and care than a larger volume of water.