Hardy Fish

Betta fish can be happy in that small a tank, and they can be very hardy.

I'm going with what WB said. My neighbor is " the funny fish guy" When we meet he told me not to worry. He isn't growing pot in the garage it is his fish. That scared me away for a while but he Is pretty interesting. He helped my daughter set up with hardy fish for a school project. She had the preaty fish there and all non salt water. I will try to ask him if I remember. But you can always go down to a real fish store. Not wal-mart and ask them what they suggest. 

Good luck

Gold fish.  (member of the carp family)   allow 1 inch of fish per gallon of water unless it is aerated,  a filter will work just fine to keep the surface of the water moving.
you will not need a heater.
 
do not over stock the tank for the first couple of weeks,  the nitrogen will build up
and kill the fish.

Yep a Betta or gold fish  

I have never had any luck with goldfish. Not that I am a fish fanatic or anything. But I had a betta once and eventually had to give it away. It lived for so many years.. A&nbspretty little thing too.

Beta, they are quite attractive and darn near undestructable!  ....[size=1]but they are hard to housebreak.[/size]

Yep, beta!  My daughter is at college and has one that lives in a little fish bowl.  She puts plastic wrap over the top of him and brings him with her when she comes home.  Her first year there she worked in the lab with rats.  So needless to say, she has her own apartment now, but she also has a rat.  I kind of like the thing and it's the perfect pet for an animal girl in a confined space.
 
Enjoy College!

I've had a wide variety of success with beta.  I've had some that survived a couple years and others that survived a couple weeks.  I've had very little success in keeping them in bowls - the one that lived a couple years did so when I had a heated tank.
 
Guppies are extremely hardy and I've kept them in just regular gold fish bowls in my bedroom back in high school.  I had more success with them than I ever did with the beta fish.  However - they are little breeding machines.  Ended up with more babies than I knew what to do with - and that was even with letting the parents eat them.
 
However, the hardiest of them all and somewhat cool looking was my zebra fish.  He survived extreme heat and seemed to live forever compared to my other fish.  I originally had him in my heated fish tank, but when I gave up on that I swapped him into just a standard gold-fish bowl with no heat & he was happy as a clam.  Heck, when we moved, he moved in a mason jar & lived in that for a couple weeks before finally being put back into a proper bowl. &nbsplus he looked cool & different w/ his blueish-purplish stripes.  Here is a link w/ some photos:
 
http://en.wikipedia.org/wiki/Zebrafish

i have three bettas and they are amazing my oldest one sirius just died[] but he lived for four years the ones i have now we've had for...the oldest one is about two years i think...so they are really hardy little fish but if you have a 5 gallon tank i suggest getting some females because you can put them together in one tank and they wont fight the females are kind of ugly but they can be pretty you just have to keep your eyes peeled for the good ones lol
and goldfish they are awesome! lol