What kind of fish can I put in a 1 gallon tank?

Is there any kind of fish that I can put in one of those little 1 gallon tanks? A little tetra or something? I am not a hobbyist; I just want a little fish tank next to my bed so I am looking for something that can fit in one of those. I don't want a snail. Maybe a little African frog or something? If there really is nothing that can fit in that small of a tank then what about a 5 gallon? 5 gallons is as big as I can go next to my bed. Please don't be rude. I will do my research on suggested fishes but I don't even know where to start...